Added potential Muslim holy orders

Still basic version, no flags yet, etc
Add compositions

Troop compositions are placeholder
Nerf Catholic holy orders a bit
On second thought...

Let's leave messing with mercs and holy orders to Ben.
Set religions and added flags
Starting to fill out new holy orders
Add basic decisions
Remove unnecessary events

Rulers won't be allowed to borrow money from these new holy orders.
First localization round complete

Curiously enough, the SoA holy order events use `hide_window = yes`
province events. I'm wondering if those simply aren't hidden or if
there's something I missed when I was testing such events earlier.
The Saqaliba are in!

Plus, donating to these Muslim holy orders will no longer cause the
grandmaster to awkwardly thank Christ.
Added decision localization

Also added some (still kind of placerholdery) flavor text for the
forming events.
Merge remote-tracking branch 'origin/beta' into holy_orders
Add decision icons
Integration with new holy order recruit mechanic
Proper title history

Also moved localization so it's all together
Updated Changelog