refactor: restructure x/consortium

[0Tech]

Description

closes: #489

Motivation and context

Refer to #489.

Checklist:

• I followed the contributing guidelines and code of conduct.
• I have added a relevant changelog to CHANGELOG.md
• I have added tests to cover my changes. [no need]
• I have updated the documentation accordingly. [no need]
• I have updated API documentation client/docs/swagger-ui/swagger.yaml [no need]

[codecov]

Codecov Report

Merging #493 (15f6bbc) into main (396a1fe) will increase coverage by 0.04%.
The diff coverage is 76.19%.

@@            Coverage Diff             @@
##             main     #493      +/-   ##
==========================================
+ Coverage   56.75%   56.80%   +0.04%     
==========================================
  Files         777      777              
  Lines       83389    83344      -45     
==========================================
+ Hits        47331    47341      +10     
+ Misses      33004    32951      -53     
+ Partials     3054     3052       -2     

Impacted Files	Coverage Δ
x/consortium/keeper/genesis.go	19.23% <19.23%> (ø)
x/consortium/keeper/keeper.go	90.00% <66.66%> (ø)
x/consortium/keeper/proposal.go	83.33% <83.33%> (ø)
simapp/app.go	86.94% <100.00%> (ø)
x/consortium/client/testutil/grpc.go	94.64% <100.00%> (ø)
x/consortium/client/testutil/suite.go	100.00% <100.00%> (ø)
x/consortium/keeper/grpc_query.go	65.90% <100.00%> (+3.40%)	⬆️
x/consortium/keeper/handler.go	58.33% <100.00%> (ø)
x/consortium/keeper/keys.go	100.00% <100.00%> (ø)
x/consortium/keeper/params.go	100.00% <100.00%> (ø)
... and 4 more

[0Tech]

I should add tests to increase the coverage. Let me handle it on the separate issue later.

[zemyblue]

LGTM