x/gov: Proto Tx CLI command

[aaronc]

ref: #5864

This PR implements protobuf tx CLI and REST endpoints for the x/gov module and in addition provides an example case of how to setup these commands with an interface handled by a oneof at the app codec level. ADR 021 was updated to reflect the approach demonstrated in this PR.

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[codecov]

Codecov Report

Merging #5942 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #5942   +/-   ##
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  Coverage   58.23%   58.23%           
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  Files         396      396           
  Lines       23621    23621           
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  Hits        13756    13756           
  Misses       8905     8905           
  Partials      960      960           

[lgtm-com]

This pull request introduces 3 alerts when merging a4dab80 into 8eb4808 - view on LGTM.com

new alerts:

• 3 for Useless assignment to field

[lgtm-com]

This pull request introduces 3 alerts when merging 9437697 into d10de8a - view on LGTM.com

new alerts:

• 3 for Useless assignment to field

[aaronc]

@alexanderbez I ran into some cyclic import issues here trying to import codec/std in x/gov/simulation. My sense is that simulation should be able to use codec/std in general. But then x/gov imports x/gov/simulation. I was able to solve the issue by changing several x/gov references to x/gov/types.

Going forward, I have the thought that x/... modules shouldn't import simulation at all. The only reason they do is because of AppModuleSimulation afaik. Wonder if you have any thoughts on that.

[alexanderbez]

Yeah I agree they should not need to import simulation if necessary.

[alexanderbez]

LGTM @aaronc. Just a few minor nitpicks on variables.

[alexanderbez]

ACK 🎉

[aaronc]

Okay, all that stuff should be resolved now @alexanderbez