Some cleanups in base registry instantiation
Don't use Horde_Auth::factory

One of the reasons we have global injector factories.  Additionaly, the
built-in Horde_Auth factory is non-optimized since it searches for the
package driver name first, rather than a full classname (which Horde
always provides).
Deprecate Horde_Auth::factory()
The gettext bind methods only need to be called once per page access

This saves up to 40+ bindtextdomain()/bind_textdomain_codeset() calls
per access.
This needs to match base class' signature
Only log logout message if there is a currently existing session
[mms] Move configuration loading code to Horde_Registry_Loadconfig class.

Horde::loadConfiguration() still works for H5, but is now deprecated.