Remove prefetch functionality

[torao]

Description

This PR removes the following features added in LBM SDK based on the result of #582 and revets to the same implementation as Cosmos SDK.

• Prefetch behavior on gRPC endpoint and storage layer
• Parallel writes

However, the following features are corrections that should be made in #595, so this PR does nothing.

• Remove CacheManager
• Revert back to fastcache

closes: #582

[codecov]

Codecov Report

Merging #596 (09474e0) into main (728aea5) will increase coverage by 3.05%.
The diff coverage is 73.91%.

@@            Coverage Diff             @@
##             main     #596      +/-   ##
==========================================
+ Coverage   57.53%   60.59%   +3.05%     
==========================================
  Files         796      814      +18     
  Lines       87526    94798    +7272     
==========================================
+ Hits        50362    57446    +7084     
- Misses      34025    34098      +73     
- Partials     3139     3254     +115     

Impacted Files	Coverage Δ
baseapp/abci.go	61.82% <ø> (-0.24%)	⬇️
baseapp/grpcrouter.go	85.93% <ø> (-1.74%)	⬇️
server/mock/store.go	21.42% <ø> (-1.58%)	⬇️
simapp/ante_handler.go	0.00% <0.00%> (ø)
store/cachekv/store.go	87.83% <ø> (-0.48%)	⬇️
store/cachemulti/store.go	9.52% <0.00%> (+1.19%)	⬆️
store/dbadapter/store.go	100.00% <ø> (+7.31%)	⬆️
store/gaskv/store.go	100.00% <ø> (ø)
store/iavl/store.go	61.66% <0.00%> (+1.34%)	⬆️
store/iavl/tree.go	89.65% <ø> (ø)
... and 55 more