[firefox] make ./mach try work out-of-the-box

[jankeromnes]

From an IRC discussion today on Mozilla's #ateam channel:

19:49:54 ahal> janx: pushed a patch up to review in no time with the janitor!
19:50:49 janx> Whoa thanks for letting me know! :D any annoying problems we could fix?
19:57:17 ahal> janx: I'd mostly like to be able to push to try with |mach try|
19:57:30 ahal> though I guess that's hard to solve securely
19:58:33 janx> ahal: we're planning to add a "sign in with Bugzilla" to automatically deploy your API key to your containers (and also work with Bugzilla so that Janitor API keys are scope-limited, e.g. only try access and not L3, and maybe time-limited too)
20:00:09 ahal> that would be cool
20:00:21 ahal> I don't care about pushing directly, try access is all I would care about
20:00:43 janx> ahal: thanks a lot for the feedback! I hope we can do this within a few months

[notriddle]

Doesn't that still require user-specific authentication?

[jankeromnes]

It does, but we could achieve this with a "sign in with Bugzilla" integration (similar to GitHub's OAuth2 flow, which would result in a Bugzilla API token that we could add to users' default configuration files).