Mobstate Refactor (#13389)

Refactors mobstate and moves mob health thresholds to their own component

Co-authored-by: DrSmugleaf <drsmugleaf@gmail.com>

Content.Server/Nuke/NukeComponent.cs

@@ -1,4 +1,5 @@
 using System.Threading;
+using Content.Server.Explosion.EntitySystems;
 using Content.Shared.Containers.ItemSlots;
 using Content.Shared.Explosion;
 using Content.Shared.Nuke;