Blender Git Loki

Fix T72619: Fix/implement support of particle modifiers in liboverride.

Some modifiers (like particle system, but also some other physics
simulations) require extra steps besides creating the modifier itself,
so had to switch to higher-level `ED_object_modifier_add()` to add
inserted modifiers in an overriding object data-block.

Due to how particle modifier handles copying, some extra nasty
hacks/work-around were also needed to get it working.