WIP implement solo machine client

[colin-axner]

Closes: #5382

Description

needs rest of client_state_test and update_test + misbheaviour_test

if you wanna start browsing this work, verifyXYZ funcs and usage of a commitment Prefix/Proof (SignaturePrefix/SignatureProof) is the juiciest part

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For contributor use:

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• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
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For admin use:

• Added appropriate labels to PR (ex. WIP, R4R, docs, etc)
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[lgtm-com]

This pull request introduces 1 alert when merging c993f95 into f92f6c9 - view on LGTM.com

new alerts:

• 1 for Expression has no effect

[lgtm-com]

This pull request introduces 2 alerts when merging c7e2b38 into 1db967b - view on LGTM.com

new alerts:

• 1 for Useless assignment to local variable
• 1 for Expression has no effect

[codecov]

Codecov Report

Merging #6115 into master will decrease coverage by 0.43%.
The diff coverage is 24.56%.

@@            Coverage Diff             @@
##           master    #6115      +/-   ##
==========================================
- Coverage   54.87%   54.44%   -0.44%     
==========================================
  Files         446      454       +8     
  Lines       26976    27285     +309     
==========================================
+ Hits        14802    14854      +52     
- Misses      11129    11387     +258     
+ Partials     1045     1044       -1     

[fedekunze]

ideally they should be sorted according to their ICS number imo

Suggested change

	const (
	Tendermint ClientType = iota + 1 // 1
	Localhost
	SoloMachine
	const (
	SoloMachine ClientType = iota + 1 // 1
	Tendermint
	Localhost

[colin-axner]

closing in favor of using a branch on the sdk repo