New shotgun reload system + animations

Added ability to load single shells + remade shotgun animations. Animations are kind of WIP and I'm struggling with some configuration glitches (switching between default pose & gesture) but hopefully it can be fixed.

[chevalier]

This is amazing and although maybe tpo dramatic a word.. unprecendented with the engine code. Would ask how you stop the reloading process? Would also ask that I'm assuming each shotgun round is an individual round in inventory?

[sll]

Awesome, least you got aid of the crappy mechanism of the Arma3 shotgun reloading system

[FlyingVolvo]

I presume holding down LMB is what stops you from cycling the action immediately after a round, or something like that?