Bitbucket webook trigger fails on private projects

[agjohnson]

The webhook from the Bitbucket webhook post seems like it may have changed. The webhook look up is failing because the repository URL on private projects is presented from Bitbucket as an https URL and we are expecting an ssh URL.

Can be reproduced by adding a project pointing to a private repository on Bitbucket and pushing a commit up. A 404 failure from the webhook is logged on Bitbucket's side.

[agjohnson]

New webhooks use a 2.0 webhook API, which doesn't work with our current implementation. Also, there are problems getting the project from URL, so #2433 just adds an explicit project webhook endpoint for each provider.