Allow repositories to be deleted using `./bin/remove`.

Summary: Currently, repositories can be deleted using `./bin/repository delete`. It makes sense to expose this operate to the `./bin/remove` script as well, for consistency.

Test Plan: Deleted a repository with `./bin/remove rTEST`.

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9350