feat: implement F1 farming rewards distribution PoC

[dongsam]

Description

closes: #91

Bullet Points

PoC (this PR)

• Stake
• Unstake
• Harvest
• Test codes

MVP(todo next PR)

• Invariant checks
• Documentation
• CLI
• gRPC query endpoints

References

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• Appropriate labels applied
• Targeted PR against correct branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[codecov]

Codecov Report

Merging #100 (2187194) into master (72748af) will decrease coverage by 1.50%.
The diff coverage is 75.18%.

❗ Current head 2187194 differs from pull request most recent head bf27b36. Consider uploading reports for the commit bf27b36 to get more accurate results

@@            Coverage Diff             @@
##           master     #100      +/-   ##
==========================================
- Coverage   56.88%   55.38%   -1.51%     
==========================================
  Files          24       23       -1     
  Lines        1830     1728     -102     
==========================================
- Hits         1041      957      -84     
+ Misses        682      662      -20     
- Partials      107      109       +2     

Impacted Files	Coverage Δ
x/farming/abci.go	0.00% <0.00%> (ø)
x/farming/keeper/grpc_query.go	88.57% <ø> (-1.38%)	⬇️
x/farming/keeper/keeper.go	77.77% <ø> (+4.44%)	⬆️
x/farming/simulation/decoder.go	6.66% <ø> (+1.40%)	⬆️
x/farming/types/keys.go	0.00% <0.00%> (ø)
x/farming/types/params.go	80.39% <ø> (+3.34%)	⬆️
x/farming/types/staking.go	0.00% <ø> (ø)
x/farming/keeper/epoch.go	75.00% <66.66%> (-2.78%)	⬇️
x/farming/keeper/plan.go	61.76% <66.66%> (-3.93%)	⬇️
x/farming/keeper/genesis.go	76.31% <83.33%> (+1.31%)	⬆️
... and 4 more

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