fix: validation swap msg and offerCoinFee ceiling

[dongsam]

Description

closes: #435

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

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Before we can merge this PR, please make sure that all the following items have been checked off. If any of the checklist items are not applicable, please leave them but write a little note why.

• [ ] 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[bot]]

Codecov Report

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

:exclamation: 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%)	:arrow_down:
x/liquidity/types/swap.go	79.10% <60.00%> (+0.78%)	:arrow_up:
x/liquidity/keeper/liquidity_pool.go	84.03% <100.00%> (+2.22%)	:arrow_up:
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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