Better format registration features documentation

The following discussion from !133670 (merged) should be addressed:

• @axil started a discussion: (+1 comment)

  I'm wondering if this note is out of place 🤔

  Should it rather be in the parent section ## Registration Features Program.

  I also thought we could use a table for all those features that keep being added in various versions

https://docs.gitlab.com/ee/administration/settings/usage_statistics.html#registration-features-program