[c2771] Use SetFactionTemporary on a larger scale. Requires C-MaNGOS 12402

* Change all escort/ follow scripts to use SetFactionTemporary with RESTORE_RESPAWN to simplify and unify code
* Change a few (not all) other scripts as well to use SetFactionTemporary instead of setFaction to have better scope control.

* Use TOGGLE_FLAG modifiers to handle required UNIT_FLAG changes on faction change of DireMaul, Prince Tortheldrin so that he works properly now
* Improve script for Aquementas a little bit, so that he will work if attacked by a player's pet

(based on commit 4de904b)