Change all of body system to use entities and components (#2074)

* Early commit

* Early commit 2

* merging master broke my git

* does anyone even read these

* life is fleeting

* it just works

* this time passing integration tests

* Remove hashset yaml serialization for now

* You got a license for those nullables?

* No examine, no context menu, part and mechanism parenting and visibility

* Fix wrong brain sprite state

* Removing layers was a mistake

* just tear body system a new one and see if it still breathes

* Remove redundant code

* Add that comment back

* Separate damage and body, component states, stomach rework

* Add containers for body parts

* Bring layers back pls

* Fix parts magically changing color

* Reimplement sprite layer visibility

* Fix tests

* Add leg test

* Active legs is gone

Crab rave

* Merge fixes, rename DamageState to CurrentState

* Remove IShowContextMenu and ICanExamine

Content.Shared/GameObjects/Components/Mobs/State/SharedMobStateManagerComponent.cs

@@ -97,9 +97,9 @@ namespace Content.Shared.GameObjects.Components.Mobs.State
 
         public void OnHealthChanged(HealthChangedEventArgs e)
         {
-            if (e.Damageable.CurrentDamageState != CurrentDamageState)
+            if (e.Damageable.CurrentState != CurrentDamageState)
             {
-                CurrentDamageState = e.Damageable.CurrentDamageState;
+                CurrentDamageState = e.Damageable.CurrentState;
                 CurrentMobState.ExitState(Owner);
                 CurrentMobState = Behavior[CurrentDamageState];
                 CurrentMobState.EnterState(Owner);