R1:13d96e63776f

Introduce "bin/repository" for repository management

Summary:
Nothing new or exciting here yet, just moving the random scripts/repositories/ things to bin/repository. Also add `repository list`.

(Console stuff comes from D2841.)

Test Plan: Ran `repository list`, `repository pull`, `repository discover`, `repository discover --verbose`, `repository help`.

Reviewers: jungejason, vrana

Reviewed By: vrana

CC: aran

Differential Revision: https://secure.phabricator.com/D2849