Load bountysource.raml from a public git repo

Right now it is duplicated in (and loaded from) this repo.

The new public repo will be the place that people submit pull requests for API changes. Once you create the repo you'll also need to point a link to it in the Contributing section of the docs.

Locate the current bountysource.raml loading path and the docs' Contributing section. First verify how the existing copy is loaded, then establish the public Git repository as the source and add its link to Contributing; done means API changes can be submitted there and the docs point to it.

Written by the indexing model from the issue text.