chore: add schema validation to yaml for documentation

[castastrophe]

Description

This adds a schema validation task to each component which will check all metadata files for valid formatting and that it aligns with the defined rules in ./schemas/documentation.schema.json.

This validation can be run ad-hoc and runs as part of the lint-staged task to prevent new invalid schema from being committed (can still be overwritten with --no-verify).

How and where has this been tested?

Please tag yourself on the tests you've marked complete to confirm the tests have been run by someone other than the author.

Validation steps

Add an invalid entry to the components/accordion/metadata/*.yml (i.e., foo: bar):

• yarn validator accordion: should report the error to the console
• yarn validate: should report success for other components and report the failure for accordion's schema
• Try to commit the error to the branch. Expect the commit to fail with the following:

To-do list

• I have read the contribution guidelines.
• If my change impacts documentation, I have updated the documentation accordingly.
• ✨ This pull request is ready to merge. ✨

[github-actions]

File metrics

Summary

Total size: 3.94 MB^*

🎉 No changes detected in any packages

* Size determined by adding together the size of the main file for all packages in the library.
* Results are not gzipped or minified.
* An ASCII character in UTF-8 is 8 bits or 1 byte.

[github-actions]

🚀 Deployed on https://pr-2518--spectrum-css.netlify.app

[mdt2]

Nice addition! Just left a context question, but this should be good to go, it's working well on my end.