This allows fetching of an individual repository, with the given ID. The

IDs are specific to the HostingServices, and are provided when listing

repositories.
GitHub's remote repository IDs have been updated to provide both the

owner and repository name as the ID, instead of the numeric ID. This is

required in order to actually fetch repository information.

Unit tests pass.
Tested manually with the upcoming web API additions, with both valid and

invalid repository IDs.