Add the pagure_distgit 3rd party extension for pagure
This 3rd party extension has a dedicated database model expending
pagure's database model to store information about monitoring status of
a project.
It also has two new endpoints, one to retrieve the current monitoring
status of a project, the second to update it.
These two endpoints are then leveraged in the srcfpo theme of pagure to
display the current monitoring status of the package and update it.
Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>