* lint: golint issue fixes

- on my local machine golint is a lot stricter than the bot so slowly going through and fixing things.

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

* more fixes from golint

* remove isPeerPersistentFn

* add changelog entry

* libs/common: Refactor libs/common 5

- move mathematical functions and types out of `libs/common` to math pkg
- move net functions out of `libs/common` to net pkg
- move string functions out of `libs/common` to strings pkg
- move async functions out of `libs/common` to async pkg
- move bit functions out of `libs/common` to bits pkg
- move cmap functions out of `libs/common` to cmap pkg
- move os functions out of `libs/common` to os pkg

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

* fix testing issues

* fix tests

closes #41417

woooooooooooooooooo kill the cmn pkg

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

* add changelog entry

* fix goimport issues

* run gofmt

* libs/common: refactor libs/common 2

- move random function to there own pkg

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

* change imports and usage throughout repo

* fix goimports

* add changelog entry

* 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

* Remove unnecessary type conversions

* Consolidate repeated strings into consts

* Clothe return statements

* Update blockchain/v1/reactor_fsm_test.go

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

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

Contributes to #3262

* go routines in blockchain reactor

* Added reference to the go routine diagram

* Initial commit

* cleanup

* Undo testing_logger change, committed by mistake

* Fix the test loggers

* pulled some fsm code into pool.go

* added pool tests

* changes to the design

added block requests under peer

moved the request trigger in the reactor poolRoutine, triggered now by a ticker

in general moved everything required for making block requests smarter in the poolRoutine

added a simple map of heights to keep track of what will need to be requested next

added a few more tests

* send errors to FSM in a different channel than blocks

send errors (RemovePeer) from switch on a different channel than the
one receiving blocks
renamed channels
added more pool tests

* more pool tests

* lint errors

* more tests

* more tests

* switch fast sync to new implementation

* fixed data race in tests

* cleanup

* finished fsm tests

* address golangci comments :)

* address golangci comments :)

* Added timeout on next block needed to advance

* updating docs and cleanup

* fix issue in test from previous cleanup

* cleanup

* Added termination scenarios, tests and more cleanup

* small fixes to adr, comments and cleanup

* Fix bug in sendRequest()

If we tried to send a request to a peer not present in the switch, a
missing continue statement caused the request to be blackholed in a peer
that was removed and never retried.

While this bug was manifesting, the reactor kept asking for other
blocks that would be stored and never consumed. Added the number of
unconsumed blocks in the math for requesting blocks ahead of current
processing height so eventually there will be no more blocks requested
until the already received ones are consumed.

* remove bpPeer's didTimeout field

* Use distinct err codes for peer timeout and FSM timeouts

* Don't allow peers to update with lower height

* review comments from Ethan and Zarko

* some cleanup, renaming, comments

* Move block execution in separate goroutine

* Remove pool's numPending

* review comments

* fix lint, remove old blockchain reactor and duplicates in fsm tests

* small reorg around peer after review comments

* add the reactor spec

* verify block only once

* review comments

* change to int for max number of pending requests

* cleanup and godoc

* Add configuration flag fast sync version

* golangci fixes

* fix config template

* move both reactor versions under blockchain

* cleanup, golint, renaming stuff

* updated documentation, fixed more golint warnings

* integrate with behavior package

* sync with master

* gofmt

* add changelog_pending entry

* move to improvments

* suggestion to changelog entry