Re-add Ruby Parser to GitLab Data Seeder

What does this MR do and why?

The Ruby Parser was removed when V2 YAML seeding (!106325 - merged) was merged.

Re-adding this parser back in.

How to set up and validate locally

If using a fresh GDK installation

$ bundle exec rake db:seed && bundle exec rake db:seed_fu

$ gdk start db
$ bundle exec rake "ee:gitlab:seed:awesome_co[beautiful_data.rb,1]"
Seeding AwesomeCo demo data for Administrator

$ bundle exec rails c
pry(main)> Group.last #=> #<Group @beautiful_data-root>
pry(main)> Group.last.labels #=> (same labels as defined in `beautiful_data.rb`)

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.