feat(yaml): support schema name for 'schema' option

[kt3k]

This PR adds handling of string input for schema option for parse and stringify. This prepares for #5117

(Note: I plan to remove Schema class input for schema option at 1.0.0, which prevents exposing internal details of schema implementation as public APIs.)

This PR also removes the references to private types DumperStateOptions LoaderStateOptions from public types. This prepares for #3764

[codecov]

Codecov Report

Attention: Patch coverage is 74.46809% with 12 lines in your changes missing coverage. Please review.

Project coverage is 92.71%. Comparing base (65d4650) to head (c1a5134).
Report is 4 commits behind head on main.

Files	Patch %	Lines
yaml/schema/mod.ts	62.50%	12 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5118      +/-   ##
==========================================
- Coverage   92.72%   92.71%   -0.01%     
==========================================
  Files         479      480       +1     
  Lines       38305    38350      +45     
  Branches     5394     5400       +6     
==========================================
+ Hits        35520    35558      +38     
- Misses       2732     2739       +7     
  Partials       53       53              

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[iuioiua]

This seems like two PRs in one.

[iuioiua]

Nice