Add historic removals

What does this MR do and why?

This MR adds 14.* removals .yml files to the /data/removals directory in order to smooth our transition toward Docs as the SSOT for deprecations and removals.

This MR does not change any existing processes and it does not overwrite any existing files.

A future iteration will propose a redesign of the Docs pages for deprecations and removals.

Screenshots or screen recordings

These are strongly recommended to assist reviewers and reduce the time to merge your change.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Run bundle exec gitlab:docs:compile_deprecations
2. Observe no changes made to doc/update/deprecations.md with git status
3. Run bundle exec gitlab:docs:check_deprecations

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.