Add "forms" for topics, posts, bbc settings. Fixes.

Signed-off-by: Norv <a.w.norv@gmail.com>
Introduce Action class, with the purpose to figure out the subaction and call it.
Rework the existing "form-based" controllers to use it: get rid of some redundancy in subactions calls
and make some of the existing arrays more 'alike'.

Signed-off-by: Norv <a.w.norv@gmail.com>
Update existing controllers using 'forms' to initialize themselves, and some to Actions.

Signed-off-by: Norv <a.w.norv@gmail.com>
Add permissions to Action class. Convert more files.

Signed-off-by: Norv <a.w.norv@gmail.com>
Quick prettify ManageMaintenance.

Signed-off-by: Norv <a.w.norv@gmail.com>