Add a rubocop that forbids `redirect_to` inside a controller `destroy` action without an explicit `status`

The following discussion from !11000 (merged) should be addressed:

• @rspeicher started a discussion: (+2 comments)

  So @DouweM and I talked about this a bit -- this is necessary to avoid a branch (or in this case, tag) deletion from also deleting the project -- see https://gitlab.com/gitlab-org/gitlab-ce/commit/924e4b370013ae3a8448a2a68e6a4d353b23b699

  This seems like a safeguard that's too critical to be relying on us remembering to send along a specific HTTP status code with a redirect. I'm not sure what a better solution would be.