Merge: shibuqam: provide a basic auth web service to simplify the use of `shibuqam`

Configuring a shibboleth client is a PITA.
So why not configure it once with an simple auth service that allows servers to delegate their authentication to it?

This is the point of the new server `shibuqamoauth`.

Please review because I'm not a security expert and I do not want to get to much exploitable flaws.

Pull-Request: #2279
Reviewed-by: Alexis Laferrière <alexis.laf@xymus.net>
Reviewed-by: Jean-Philippe Caissy <jpcaissy@piji.ca>