When reviewboard server contains several repositories (currently we get 400)

it is hard to know which already exists and which are accessible for a user.

To prevent granting all users to staff, we propose this new rbtools command.

We expect people could be interested in such command and maybe someone extend

it (filtering options, improve formatting ...)

can list repositories from any working directory (inside or outside a local scm repository)

Repositories on https://reviews.reviewboard.org:
tool | name                | path                                              
-----+---------------------+---------------------------------------------------
Git  | Djblets             | git://github.com/djblets/djblets.git              
[...]
Git  | Reviewboard Persona | git://github.com/smacleod/reviewboard-persona.git
[...]