Add in rubocop and yamlline config and pipeline checks

Resolves #9 (closed)

Noticed when I was doing MRs that we don't have lint files for Ruby / Yaml and that we had an existing issue for it.

This MR brings in a curated list of starter rules from gitlab-qa and gitlab-ce for the Rubocop and Yamllint linters. It also adds new starter commit checks for gitlab-ci along with some small general fixes.