Apply feedback of Liquidity module QA

[dongsam]

Description

Apply feedback in Notion Page, #170

• remove unused make scripts
• Refactoring TransactAndRefundSwapLiquidityPool
• Modify to return errors instead of panic, add error types
• Simplify Multiple if than else cases on swap.go
• Add comment for new swap model, breakFlag, appendFlag, etc
• Add test scripts(will proceed through separate PR)

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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]

Codecov Report

Merging #215 (e371af1) into develop (5c05566) will decrease coverage by 0.59%.
The diff coverage is 65.38%.

❗ Current head e371af1 differs from pull request most recent head 2854273. Consider uploading reports for the commit 2854273 to get more accurate results

@@             Coverage Diff             @@
##           develop     #215      +/-   ##
===========================================
- Coverage    83.43%   82.84%   -0.60%     
===========================================
  Files           20       20              
  Lines         2349     2215     -134     
===========================================
- Hits          1960     1835     -125     
  Misses         209      209              
+ Partials       180      171       -9     

Impacted Files	Coverage Δ
x/liquidity/types/utils.go	100.00% <ø> (ø)
x/liquidity/keeper/invariants.go	58.78% <42.85%> (ø)
x/liquidity/keeper/swap.go	85.71% <42.85%> (-0.12%)	⬇️
x/liquidity/types/swap.go	77.91% <60.56%> (-3.91%)	⬇️
x/liquidity/keeper/liquidity_pool.go	78.66% <80.00%> (+0.74%)	⬆️
x/liquidity/keeper/batch.go	86.36% <0.00%> (-4.55%)	⬇️

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