Merged to pbts branch in #7541

This pull request merges in the changes for implementing Proposer-based timestamps into `master`. The power was primarily being done in the `wb/proposer-based-timestamps` branch, with changes being merged into that branch during development. This pull request represents an amalgamation of the changes made into that development branch. All of the changes that were placed into that branch have been cleanly rebased on top of the latest `master`. The changes compile and the tests pass insofar as our tests in general pass.

### Note To Reviewers
 These changes have been extensively reviewed during development. There is not much new here. In the interest of making effective use of time, I would recommend against trying to perform a complete audit of the changes presented and instead examine for mistakes that may have occurred during the process of rebasing the changes. I gave the complete change set a first pass for any issues, but additional eyes would be very appreciated. 

In sum, this change set does the following:
closes #6942 
merges in #6849

## Description

Internalize some libs. This reduces the amount ot public API tendermint is supporting. The moved libraries are mainly ones that are used within Tendermint-core.

## Description

- Add `context.Context` to Privval interface

This pr does not introduce context into our custom privval connection protocol because this will be removed in the next release. When this pr is released.

## Description

This PR aims to make the crypto.PubKey interface more intuitive. 

Changes: 

- `VerfiyBytes` -> `VerifySignature`

Before `Bytes()` was amino encoded, now since it is the byte representation should we get rid of it entirely?

EDIT: decided to keep `Bytes()` as it is useful if you are using the interface instead of the concrete key

Closes: #XXX

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>

* test-vectors for backwards compatibility:

 - copy & paste test-vectors from v0.33.5 to ensure
 backwards compatibility for vote's SignBytes

* WIP: everything besides time seems to match :-/

* almost

* Found the culprit: field nums weren't consecutive ints ...

* fix order of partset header too

* this last votes-related test can easily be fixed

* some minor changes and fix last failing test

* move proto types back to stdtime, fix various linting

* use libs/protoio

* remvoe commented code

* add comments

* fix tests

* uncomment testscases

* dont ignore error panic

* fix signable test

* fix happy path testing

* fix comment

Co-authored-by: Marko Baricevic <marbar3778@yahoo.com>

## Description

these proto files are meant to help unblock ibc in their quest of migrating the ibc module to proto.

Closes: #XXX

* format: add format cmd & goimport repo

- replaced format command
- added goimports to format command
- ran goimports

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* fix outliers & undo proto file changes

closes #3602

Co-authored-by: Anton Kaliaev <anton.kalyaev@gmail.com>

Refs #3262

* Pin range scope vars

* Don't disable scopelint

This PR repairs linter errors seen when running the following commands:
golangci-lint run --no-config --disable-all=true --enable=scopelint

Contributes to #3262

Fixes #2740

* Align Proposal message with spec

* Update spec

* catch up with amino changes in
https://github.com/tendermint/go-amino/pull/222

* WIP: update to amino v0.13.0

* update to fixed amino release

* switch to amino for SignBytes and add Reply with error message

- currently only Vote is done

* switch Reply type in socket for other messages

 - add error description on error

* add TODOs regarding error handling

* address comments from peer review session (thx @xla)

 - contains all changes besides the test-coverage / error'ing branches

* increase test coverage:

 - add tests for each newly introduced error'ing code path

* return error if received wrong response

* add test for wrong response branches (ErrUnexpectedResponse)

* update CHANGELOG_PENDING and related documentation (spec)

* fix typo: s/CanonicallockID/CanonicalBlockID

* fixes from review

- use cmn.Fingerprint and %X

Signatures are now []byte, which saves on the number of bytes after
amino encoding

(squash this) address Ismail's comment

This reverts commit 58d0c8de89.

This reverts commit d02c5d1e30.

This reverts commit 96a3502

String() and Proposal valid after serializing.
To be safe, but mainly to increase test coverage for the PR

Store it as time.Timestamp locally, encode it as RFC3339 with milliseconds
before signing the canonical form.