refactor: move vanity names to account roles pallet

[j4m1ef0rd]

Pull Request

Closes: PRO-1255

Checklist

• I am confident that the code works.
• I have updated documentation where appropriate.

Summary

• Moved the vanity name storage item to the account roles pallet.
  • Moved the related benchmark and test.
• Created a migration. Tested it with try-migration.

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 59 lines in your changes are missing coverage. Please review.

Project coverage is 72%. Comparing base (9b4b855) to head (ff9daad).
Report is 3 commits behind head on main.

Files	Patch %	Lines
state-chain/runtime/src/lib.rs	0%	21 Missing and 4 partials ⚠️
state-chain/pallets/cf-account-roles/src/lib.rs	53%	13 Missing and 1 partial ⚠️
...tate-chain/pallets/cf-account-roles/src/weights.rs	0%	14 Missing ⚠️
api/lib/src/lib.rs	0%	4 Missing ⚠️
state-chain/pallets/cf-account-roles/src/tests.rs	94%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@          Coverage Diff           @@
##            main   #4719    +/-   ##
======================================
- Coverage     72%     72%    -0%     
======================================
  Files        417     418     +1     
  Lines      69532   69447    -85     
  Branches   69532   69447    -85     
======================================
- Hits       50246   50084   -162     
- Misses     16879   16959    +80     
+ Partials    2407    2404     -3     

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[dandanlen]

I made some additions and resolved conflicts - let me know what you think .