feat!: change Coin storage model

[aleem1314]

Description

Closes: #9361

---

Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• included the correct type prefix in the PR title
• added ! to the type prefix if API or client breaking change
• targeted the correct branch (see PR Targeting)
• provided a link to the relevant issue or specification
• followed the guidelines for building modules
• included the necessary unit and integration tests
• added a changelog entry to CHANGELOG.md
• included comments for documenting Go code
• updated the relevant documentation or specification
• reviewed "Files changed" and left comments if necessary
• confirmed all CI checks have passed

Reviewers Checklist

All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.

I have...

• confirmed the correct type prefix in the PR title
• confirmed ! in the type prefix if API or client breaking change
• confirmed all author checklist items have been addressed
• reviewed state machine logic
• reviewed API design and naming
• reviewed documentation is accurate
• reviewed tests and test coverage
• manually tested (if applicable)

[orijbot]

Visit https://dashboard.github.orijtech.com?pr=9832&repo=cosmos%2Fcosmos-sdk to see benchmark details.

[codecov]

Codecov Report

Merging #9832 (a477306) into master (bdf5aee) will decrease coverage by 0.02%.
The diff coverage is 56.52%.

@@            Coverage Diff             @@
##           master    #9832      +/-   ##
==========================================
- Coverage   63.50%   63.47%   -0.03%     
==========================================
  Files         568      568              
  Lines       53257    53271      +14     
==========================================
- Hits        33819    33815       -4     
- Misses      17521    17532      +11     
- Partials     1917     1924       +7     

Impacted Files	Coverage Δ
x/bank/keeper/send.go	82.98% <40.00%> (-2.65%)	⬇️
x/bank/migrations/v044/store.go	68.42% <45.45%> (-9.36%)	⬇️
x/bank/keeper/view.go	83.33% <50.00%> (-5.10%)	⬇️
x/bank/keeper/grpc_query.go	47.88% <80.00%> (-0.37%)	⬇️
x/bank/types/key.go	70.00% <100.00%> (-1.43%)	⬇️

[amaury1093]

Nice and clean PR, thanks @aleem1314!

To fix the rosetta test, you can try to run make rosetta-data

[atheeshp]

looks good