Improve code quality widget design

The following discussions from !1984 (merged) should be addressed:

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

  @dzaporozhets @jschatz1 i think the mvp lies in the following (this still should be done for this release as discussed in the ci meeting)

  

  • file links to corresponding error lines in mr diff

  • job name corresponds to code climate docs like https://docs.codeclimate.com/docs/rubocop

• @markpundsack started a discussion:

  @dimitrieh Do we call this a "widget" publicly? Previously we've called it the "system information box", but I'm not sure that was ever public either.

• Backport documentation changes to CE (https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/1984#note_31384823)