Add an AliasLoader and associated plumbing.

Introduce a global lifecycle component interface which provides a
way to start/stop components, and will help with The Quitting Problem™
when we get around to it.

Change-Id: I6d43f354e90e8206bea3f61a74d09728c9cac5aa
Reviewed-on: http://gerrit.dmdirc.com/3520
Reviewed-by: Greg Holmes <greg@dmdirc.com>
Automatic-Compile: DMDirc Build Manager