feat: Add grpc gateway annotations

[aleem1314]

closes: #182

[codecov]

Codecov Report

Merging #183 (bcd2573) into master (8b95557) will increase coverage by 3.69%.
The diff coverage is 85.36%.

❗ Current head bcd2573 differs from pull request most recent head 562611d. Consider uploading reports for the commit 562611d to get more accurate results

@@            Coverage Diff             @@
##           master     #183      +/-   ##
==========================================
+ Coverage   56.36%   60.05%   +3.69%     
==========================================
  Files          59       56       -3     
  Lines        3717     3425     -292     
==========================================
- Hits         2095     2057      -38     
+ Misses       1351     1104     -247     
+ Partials      271      264       -7     

Flag	Coverage Δ
experimental-codecov	60.05% <85.36%> (+3.69%)	⬆️
stable-codecov	60.05% <85.36%> (+3.69%)	⬆️

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[amaury1093]

would be cool to have 1 or 2 integration tests too, for a later PR

[blushi]

@aleem1314 Now that the group module is merged, we will also need to add grpc gateway annotations to it.

[amaury1093]

It seems that this fails because of the custom code generator. Maybe we should fix it in the SDK first? ref: cosmos/cosmos-sdk#9302

[amaury1093]

Yes, this is going in the right direction (unfortunately for now). Pre-approving.

We can also remove the protoc-gen-go-cosmos2 folder.