feat: add FormatTime and ParseTimeString methods

[julienrbrt]

Description

Closes: #12658

---

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)

[codecov]

Codecov Report

Merging #12995 (d2ec08c) into main (4fe7797) will decrease coverage by 0.27%.
The diff coverage is 66.82%.

❗ Current head d2ec08c differs from pull request most recent head 44021dd. Consider uploading reports for the commit 44021dd to get more accurate results

@@            Coverage Diff             @@
##             main   #12995      +/-   ##
==========================================
- Coverage   55.87%   55.60%   -0.28%     
==========================================
  Files         646      648       +2     
  Lines       54895    54943      +48     
==========================================
- Hits        30675    30550     -125     
- Misses      21762    21929     +167     
- Partials     2458     2464       +6     

Impacted Files	Coverage Δ
baseapp/abci.go	64.09% <0.00%> (-0.33%)	⬇️
client/flags/flags.go	19.35% <0.00%> (-0.32%)	⬇️
client/rpc/status.go	66.66% <ø> (ø)
client/utils.go	34.92% <0.00%> (ø)
server/rosetta/client_online.go	1.35% <0.00%> (ø)
server/swagger.go	0.00% <0.00%> (ø)
simapp/app.go	82.66% <0.00%> (+3.55%)	⬆️
testutil/list.go	0.00% <0.00%> (ø)
types/result.go	76.74% <ø> (ø)
x/auth/tx/query.go	0.00% <ø> (ø)
... and 50 more