Moderator permissions: Can move threads,change prefix, merge, delete as spam, stick,

[Alfa1]

By default it is possible to set moderator permission to:
'Can manage threads: Yes/No'
This includes thread moving, merging, prefixing, deleting threads as spam and much more.

Most of these actions can be undone by an admin, except merging threads. Mass merging threads can destroy whole forums, so this is something to be careful about. So not everyone wants to give this functionality to their moderators or junior moderators.

This is why a hack is needed to split up 'can manage threads' permissions, so that it becomes possible to set whether a moderator can:
- Move threads
- Merge threads
- Prefix threads
- delete threads as spam
- stick threads
- unstick threads