Add option to set AI Teammate skill level.

Option for vehicle to show up during mission
Option for even larger AO

* Fix bug: if mods changed and previously selected faction no longer exists, would crash the mission
* Fixed a bug that could slow down the server significantly in long games

Fix missing civilians in faction optimization update.

Optimize faction selection code: If you had a lot of factions (like when using RHS) it could take around 20 seconds to load the factions. It now takes less than 3 seconds and runs during mission start so the faction selection UI should be much quicker too.

* Add ai teammate 'previous' loadout option
* Improve when AI teammates revive:
+ AI will only revive if they are not stopped, all players are down, or they are within 10m.
+ AI that were stopped will return to their previous position after reviving
* Fix bug when arsenal was in 'faction' mode it was empty.

Another fix to work with mods that have faction side as a string instead of a number.

Fix for mods whose config for faction side is incorrect.

Fix bug in enemy count