(rroles): Expiry system and small bugfixes.

Completed the `duration` reaction role setting implementation.
Improved the `Duration` setting type format.
Moved reaction roles to their own module.
Various small bugfixes.

bot/modules/guild_admin/reaction_roles/__init__.py

@@ -1,3 +1,5 @@
+from .module import module
+
 from . import data
 from . import settings
 from . import tracker