New configuration for sub-forums.

New forums need controller and template support, but ACLs, titles and
so on go in config.
Removing forum config values from Thread model
Thread retrieval by forum index, ACL (user_filter) enforcement.
This adds controller / form elements to send new threads to correct forum
Admin / community leader links for those with access.
Only "press" General Ramblings button when on that forum.
Link 'suggest' pages to correct subforum (General or...)
New templates for sub-forums.
Removing magic number.
Changed 'General Rambling' notification text to 'Forum Post' for now.
Disambiguate anon hashref
Change some redirects from Forum index to Forum general.
Redirect change from Forum index to Forum general
Special Forums template, like the other templates.
Prevent users replying to special announcements.

This would pre-empt our notification.
Notification name changes for different forum sub-types
Pulling forum title text from config in thread notification.

Thanks to @crazedpsyc for this one.
Moving forum access code to DDGC::Forum. Cleaning up some config access bits
Fixing newthread link for screenshots.

Should address problem raised by @moollaza
Remove 'Forum Manager Forum' link from moderation page.