This issue is related to #3107
This is a first renaming/refactoring step before reworking and removing heartbeats.
As discussed with @Liamsi , we preferred to go for a couple of independent and separate PRs to simplify review work.

The changes:

    Help to clarify the relation between the validator and remote signer endpoints
    Differentiate between timeouts and deadlines
    Prepare to encapsulate networking related code behind RemoteSigner in the next PR

My intention is to separate and encapsulate the "network related" code from the actual signer.

SignerRemote ---(uses/contains)--> SignerValidatorEndpoint <--(connects to)--> SignerServiceEndpoint ---> SignerService (future.. not here yet but would like to decouple too)

All reconnection/heartbeat/whatever code goes in the endpoints. Signer[Remote/Service] do not need to know about that.

I agree Endpoint may not be the perfect name. I tried to find something "Go-ish" enough. It is a common name in go-kit, kubernetes, etc.

Right now:
SignerValidatorEndpoint:

    handles the listener
    contains SignerRemote
    Implements the PrivValidator interface
    connects and sets a connection object in a contained SignerRemote
    delegates PrivValidator some calls to SignerRemote which in turn uses the conn object that was set externally

SignerRemote:

    Implements the PrivValidator interface
    read/writes from a connection object directly
    handles heartbeats

SignerServiceEndpoint:

    Does most things in a single place
    delegates to a PrivValidator IIRC.

* cleanup

* Refactoring step 1

* Refactoring step 2

* move messages to another file

* mark for future work / next steps

* mark deprecated classes in docs

* Fix linter problems

* additional linter fixes

* libs/common: TrapSignal accepts logger as a first parameter

 and does not block anymore
* previously it was dumping "captured ..." msg to os.Stdout
* TrapSignal should not be responsible for blocking thread of execution

Refs #3238

* exit with zero (0) code upon receiving SIGTERM/SIGINT

Refs #3238

* fix formatting in docs/app-dev/abci-cli.md

Co-Authored-By: melekes <anton.kalyaev@gmail.com>

* fix formatting in docs/app-dev/abci-cli.md

Co-Authored-By: melekes <anton.kalyaev@gmail.com>

* changelog: use issue number instead of PR number

* follow up to #3291

- rpc/test/helpers.go add StopTendermint(node) func
- remove ensureDir(filepath.Dir(walFile), 0700)
- mempool/mempool_test.go add type cleanupFunc func()

* cmd/show_validator: wrap err to make it more clear

* return a command error prior to init

* add a pending log entry

* Update CHANGELOG_PENDING.md

Co-Authored-By: alexanderbez <alexanderbez@users.noreply.github.com>

closes: #3314

* make govet linter pass

Refs #3262

* close PipeReader and check for err

* types.NewCommit

* use types.NewCommit everywhere

* fix log in unsafe_reset

* memoize height and round in constructor

* notes about deprecating toVote

* bring back memoizeHeightRound

in the attempt to fix https://circleci.com/gh/tendermint/tendermint/43165

also

    code is simplified by running gofmt -s .
    remove unused vars
    enable linters we're currently passing
    remove deprecated linters

As per conversation here: https://github.com/tendermint/tendermint/pull/3218#discussion_r251364041

This is the result of running the following code on the repo:

```bash
find . -name '*.go' | grep -v 'vendor/' | xargs -n 1 goimports -w
```

https://github.com/tendermint/tendermint/pull/2923#pullrequestreview-192065694

* Close and recreate a RemoteSigner on err

* Update changelog

* Address Anton's comments / suggestions:

 - update changelog
 - restart TCPVal
 - shut down on `ErrUnexpectedResponse`

* re-init remote signer client with fresh connection if Ping fails

- add/update TODOs in secret connection
- rename tcp.go -> tcp_client.go, same with ipc to clarify their purpose

* account for `conn returned by waitConnection can be `nil`

- also add TODO about RemoteSigner conn field

* Tests for retrying: IPC / TCP

 - shorter info log on success
 - set conn and use it in tests to close conn

* Tests for retrying: IPC / TCP

 - shorter info log on success
 - set conn and use it in tests to close conn
 - add rwmutex for conn field in IPC

* comments and doc.go

* fix ipc tests. fixes #2677

* use constants for tests

* cleanup some error statements

* fixes #2784, race in tests

* remove print statement

* minor fixes from review

* update comment on sts spec

* cosmetics

* p2p/conn: add failing tests

* p2p/conn: make SecretConnection thread safe

* changelog

* IPCVal signer refactor

- use a .reset() method
- don't use embedded RemoteSignerClient
- guard RemoteSignerClient with mutex
- drop the .conn
- expose Close() on RemoteSignerClient

* apply IPCVal refactor to TCPVal

* remove mtx from RemoteSignerClient

* consolidate IPCVal and TCPVal, fixes #3104

- done in tcp_client.go
- now called SocketVal
- takes a listener in the constructor
- make tcpListener and unixListener contain all the differences

* delete ipc files

* introduce unix and tcp dialer for RemoteSigner

* rename files

- drop tcp_ prefix
- rename priv_validator.go to file.go

* bring back listener options

* fix node

* fix priv_val_server

* fix node test

* minor cleanup and comments

privval: remove GetAddress(), memoize pubkey

* split immutable and mutable parts of priv_validator.json

* fix bugs

* minor changes

* retrig test

* delete scripts/wire2amino.go

* fix test

* fixes from review

* privval: remove mtx

* rearrange priv_validator.go

* upgrade path

* write tests for the upgrade

* fix for unsafe_reset_all

* add test

* add reset test

* config: cors options are arrays of strings, not strings

Fixes #2980

* docs: update tendermint-core/configuration.html page

* set allow_duplicate_ip to false

* in `tendermint testnet`, set allow_duplicate_ip to true

Refs #2712

* fixes after Ismail's review

* fix docs / proxy app, closes #2986

* counter_serial

* review comments

* list all possible options

* add changelog entries

previously, we're turning it off only when --populate-persistent-peers
flag was used, which is obviously incorrect.

Fixes https://github.com/cosmos/cosmos-sdk/issues/2983

* Introduce a structured logging option

* rename StructuredLog to LogFormat

* add changelog entry

* move log_format under log_level

* require block.Time of the fist block to be genesis time

Refs #2587:

```
We only start validating block.Time when Height > 1, because there is no
commit to compute the median timestamp from for the first block. This
means a faulty proposer could make the first block with whatever time
they want.

Instead, we should require the timestamp of block 1 to match the genesis
time.

I discovered this while refactoring the ValidateBlock tests to be
table-driven while working on tests for #2560.
```

* do not accept blocks with negative height

* update changelog and spec

* nanos precision for test genesis time

* Fix failing test (#2607)

* Implement issues 2386: add synchronization in lite verify and change all Certify to Verify

* Replace make(chan struct{}, 0) with make(chan struct{})

* Parameterize memroy cache size and add concurrent test

* Refactor import order

* add missing options to config.toml template and docs
Refs #2232
* config#ValidateBasic
Refs #2232
* [config] timeouts as time.Duration, not ints
Why:
- native type provides better guarantees than ", in ms" comment (harder
to shoot yourself in the leg)
- flexibility: you can change units

* stop node upon receiving SIGTERM or CTRL-Ceven during genesis sleep by setting up interrupt before starting a node

Closes #2434

* call Start, not OnStart when starting a component to avoid:

```
E[09-24|10:13:15.805] Not stopping PubSub -- have not been started yet module=pubsub impl=PubSub
```

being printed on exit

Refs #1714

* Implement BFT time

* set LastValidators when creating state in state helper

for heights >= 2

* libs: Remove usage of custom Fmt, in favor of fmt.Sprintf

Closes #2193

* Fix bug that was masked by custom Fmt!

Currently the top level directory contains basically all of the code
for the crypto package. This PR moves the crypto code into submodules
in a similar manner to what `golang/x/crypto` does. This improves code
organization.

Ref discussion: https://github.com/tendermint/tendermint/pull/1966

Closes #1956

This reverts commit 58d0c8de89.

This reverts commit d02c5d1e30.

* config: rename skip_upnp to upnp

Change default option to enable upnp.

Closes #1806

* doc updates

- fix comment and set UPNP to false in TestP2PConfig
- add UPNP to config template
- update changelog

This reverts commit 96a3502

* Switch ports 466xx to be 266xx
This is done so the default ports aren't in the linux kernel's default ephemeral port range.

* Update ABCI import

* Bump cache on circleci

* Get more verbose output for debugging

* Bump abci dependency

* Fix accidental change of a block header's hash

* pin abci release

* `unsafe_reset_all` also resets addrbook.json

When executing `unsafe_reset_all` it also clear all IP addresses from
addrbook.json. This is the expected behaviour of `unsafe_reset_all`.

* Fix tests

* improve logging statements

* use correct file

This is a maintenance change to move the private validator package out
of the types and to a top-level location. There is no good reason to
keep it under the types and it will more clearly coommunicate where
additions related to the privval belong. It leaves the interface and the
mock in types for now as it would introduce circular dependency between
privval and types, this should be resolved eventually.

* mv priv_validator to privval pkg
* use consistent `privval` as import

Follow-up to #1255

* [cmd] Turn off strict routability when using testnet cmd

Refs https://github.com/tendermint/tendermint/pull/1454

* use "testnet" instead of "it"

fix node ids

* improve testnet cmd

* allow non-validators
* configurable prefix
* populating of persistent peers

* relax permissions

* cleanup output dir every time

* do not remove dir

* remove panic comments