fix: validation swap msg and offerCoinFee ceiling

[dongsam]

Description

closes: #435

• When calculating OfferCoinFee, the decimal points are rounded up.
• Add test code for MsgSwapWithinBatch validation and OfferCoinFee calculation
• Fix reserveOfferCoinFee residual Issue due to decimal error
• Corrected the missing part of the Spec doc and updated the above.
• Update Spec docs and description, swagger

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• Targeted PR against correct branch (see CONTRIBUTING.md)
• 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 tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[codecov]

Codecov Report

Merging #436 (f4022bd) into develop (33a5ca6) will increase coverage by 1.76%.
The diff coverage is 50.00%.

❗ Current head f4022bd differs from pull request most recent head 124c9d2. Consider uploading reports for the commit 124c9d2 to get more accurate results

@@             Coverage Diff             @@
##           develop     #436      +/-   ##
===========================================
+ Coverage    83.36%   85.13%   +1.76%     
===========================================
  Files           20       20              
  Lines         2302     2596     +294     
===========================================
+ Hits          1919     2210     +291     
- Misses         218      223       +5     
+ Partials       165      163       -2     

Impacted Files	Coverage Δ
x/liquidity/types/utils.go	83.33% <37.50%> (-8.98%)	⬇️
x/liquidity/types/swap.go	79.10% <60.00%> (+0.78%)	⬆️
x/liquidity/keeper/liquidity_pool.go	84.03% <100.00%> (+2.22%)	⬆️
x/liquidity/abci.go	100.00% <0.00%> (ø)
x/liquidity/genesis.go	100.00% <0.00%> (ø)
x/liquidity/handler.go	100.00% <0.00%> (ø)
x/liquidity/types/keys.go	100.00% <0.00%> (ø)
x/liquidity/types/msgs.go	100.00% <0.00%> (ø)
x/liquidity/types/codec.go	100.00% <0.00%> (ø)
x/liquidity/types/genesis.go	100.00% <0.00%> (ø)
... and 13 more

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[jaybxyz]

LGTM