[Draft] add change base fee proposal

[thomas-nguy]

Closes: #937

Description

Allow to adjust the base fee value of the network in case it takes an absurd value

• needs to write unit tests

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• Wrote unit and integration tests
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[codecov]

Codecov Report

Merging #938 (1e2c3c8) into main (e16b7f8) will decrease coverage by 0.23%.
The diff coverage is 15.62%.

@@            Coverage Diff             @@
##             main     #938      +/-   ##
==========================================
- Coverage   59.46%   59.23%   -0.24%     
==========================================
  Files          77       79       +2     
  Lines        6237     6268      +31     
==========================================
+ Hits         3709     3713       +4     
- Misses       2343     2370      +27     
  Partials      185      185              

Impacted Files	Coverage Δ
x/feemarket/types/codec.go	0.00% <0.00%> (ø)
x/feemarket/types/proposal.go	14.28% <14.28%> (ø)
app/app.go	85.45% <100.00%> (+0.03%)	⬆️

[fedekunze]

Hmm why don't you add the base fee as a module parameter? Then we won't need to maintain additional code

[thomas-nguy]

yeah the idea is not to introduce breaking state change but if its okay to change the feemarket params, then it might be easier

[fedekunze]

let's add it as a param instead

[thomas-nguy]

#943