'manage threads' permissions for (junior) moderators

[Alfa1]

If you have junior moderators, then you can only decide to give 'manage threads' permission or not. This includes all dangerous thread related actions, like merging and deleting threads but also minor actions like open, close, approving, unapprove, stick, unstick, move threads and apply prefixes.

Giving junior mods the ability to manage threads, without being able to merge a whole forum into one thread would be much wanted.

Please consider coding more functionality to define manage threads permissions.