Add a table sticky headings filter

This wraps all tables inside a div with a class of table-sticky-headings, so that we can style them.

I basically took https://gitlab.com/gitlab-org/gitlab-docs/-/blob/main/lib/filters/introduced_in.rb and edited it to match what we needed to accomplish.

For #1076 (closed)

How to test

1. Either open locally a page that contains a table or visit the review app http://axil-filter-sticky-headings.178.62.207.141.nip.io/ee/index.html.
2. Inspect the table element with your browser's developer tools.
3. You should see <div class="table-sticky-headings"> before <table>.