[Feature] remove readvm-pool feature

[yun-yeo]

Summary of changes

close #599

Now a wasm VM can handle multi-thread query requests (ref), so we don't need this feature anymore. Also the feature seems make critical issue when loading wasm code into memory.

Report of required housekeeping

• Github issue OR spec proposal link
• Wrote tests
• Updated API documentation (client/lcd/swagger-ui/swagger.yaml)
• Added a relevant changelog entry: clog add [section] [stanza] [message]

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(FOR ADMIN) Before merging

• Added appropriate labels to PR
• Squashed all commits, uses message "Merge pull request #XYZ: [title]" (coding standards)
• Confirm added tests are consistent with the intended behavior of changes
• Ensure all tests pass

[codecov]

Codecov Report

Merging #601 (113009c) into main (3fcaa62) will decrease coverage by 0.12%.
The diff coverage is 87.09%.

@@            Coverage Diff             @@
##             main     #601      +/-   ##
==========================================
- Coverage   44.81%   44.69%   -0.13%     
==========================================
  Files         122      120       -2     
  Lines        7013     6967      -46     
==========================================
- Hits         3143     3114      -29     
+ Misses       3626     3614      -12     
+ Partials      244      239       -5     

Impacted Files	Coverage Δ
x/wasm/keeper/legacy_querier.go	33.73% <ø> (-1.50%)	⬇️
x/wasm/keeper/querier.go	33.33% <ø> (-2.06%)	⬇️
x/wasm/types/keys.go	0.00% <ø> (ø)
x/wasm/keeper/keeper.go	84.26% <78.94%> (+2.45%)	⬆️
x/wasm/keeper/contract.go	79.84% <100.00%> (+0.31%)	⬆️
x/oracle/tally.go	86.48% <0.00%> (-5.41%)	⬇️