perf: memoize bech32 encoding and decoding

[wetcod]

Description

bech32 encoding and decoding takes a lot of time, so memoize it

It is appropriate to add a layer to choose whether to access the cache or to run actual conversion.
There are too many parts that call AccAddressFromBech32 or AccAddress.String (baseapp, most modules, Json marshaling, etc.)
I am concerned that there will be many changes, so it would be better to proceed later.

Profile

AS-IS

TO-BE

Because of the performance improvement of types.AccAddress.String and types.AccAddressFromBech32,
DeliverTx is faster

-->

closes: #XXXX

---

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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 #216 (870d1b7) into v2/develop (88ab1bd) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@              Coverage Diff               @@
##           v2/develop     #216      +/-   ##
==============================================
- Coverage       53.49%   53.46%   -0.04%     
==============================================
  Files             653      652       -1     
  Lines           47376    47379       +3     
==============================================
- Hits            25343    25330      -13     
- Misses          19178    19187       +9     
- Partials         2855     2862       +7     

Impacted Files	Coverage Δ
baseapp/baseapp.go	77.94% <ø> (+0.85%)	⬆️
server/config/config.go	42.39% <ø> (+0.63%)	⬆️
server/config/toml.go	18.18% <ø> (ø)
simapp/app.go	83.96% <ø> (+0.16%)	⬆️
simapp/simd/cmd/root.go	79.84% <ø> (-1.11%)	⬇️
store/cache/cache.go	88.88% <ø> (+0.65%)	⬆️
store/cachekv/store.go	91.34% <ø> (+4.21%)	⬆️
store/iavl/store.go	66.36% <ø> (+0.29%)	⬆️
store/rootmulti/store.go	65.25% <ø> (-0.72%)	⬇️
store/types/gas.go	75.00% <ø> (+1.82%)	⬆️
... and 24 more

[egonspace]

Looks very good!