FR: Add support for local repositories

[ogarcia]

This request may seem a little strange, but it is interesting from the point of view of centralizing all repositories on the same server. The idea is that you can simply put something like this in the configuration:

repos:
  local:
    file: /srv/my/local/repo

And that the contents of the directory are simply served via HTTP in http://YOURSERVER:9129/repo/local, so that you can, apart from serving remote repositories, do the same with one or more local repositories.

This would be very convenient, since currently the only way to serve a local repository is to set up another web server separately.

Another option to address this would be for pacoloco to support the file:// scheme:

repos:
  local:
    url: file:///srv/my/local/repo

But this would duplicate the files locally, which I think is unnecessary.