feat: add new CLP tx to add liquidity to rewards bucket

[snobbee]

• add new CLP tx to add liquidity to rewards bucket
• add rewards bucket keeper functions
• add bank keeper mock object to mock bank keeper functions
• add unit tests for rewards bucket keeper functions
• add integration tests for the tx message
• add REST post endpoint

[codecov[bot]]

Codecov Report

Merging #3427 (03adcfa) into master (0c63583) will increase coverage by 0.11%. Report is 8 commits behind head on master. The diff coverage is 38.60%.

@@            Coverage Diff             @@
##           master    #3427      +/-   ##
==========================================
+ Coverage   43.35%   43.46%   +0.11%     
==========================================
  Files         166      175       +9     
  Lines       15895    16328     +433     
==========================================
+ Hits         6891     7097     +206     
- Misses       8591     8807     +216     
- Partials      413      424      +11     

Files	Coverage Δ
app/app.go	94.08% <100.00%> (+3.97%)	:arrow_up:
cmd/sifnoded/cmd/ibc-diag.go	15.74% <ø> (ø)
x/clp/types/codec.go	100.00% <100.00%> (ø)
x/clp/types/key_rewards_bucket.go	100.00% <100.00%> (ø)
x/clp/types/keys.go	84.21% <100.00%> (+0.87%)	:arrow_up:
x/clp/types/querier.go	100.00% <ø> (ø)
x/dispensation/types/types.go	100.00% <100.00%> (ø)
x/ibctransfer/helpers/conversion_helper.go	37.19% <ø> (ø)
x/ibctransfer/keeper/msg_server.go	86.95% <ø> (ø)
app/setup_handlers.go	10.52% <0.00%> (+1.83%)	:arrow_up:
... and 14 more

... and 2 files with indirect coverage changes