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/Body/Behavior/SharedLungBehaviorComponent.cs

@@ -0,0 +1,39 @@
+#nullable enable
+using Robust.Shared.Serialization;
+using Robust.Shared.ViewVariables;
+
+namespace Content.Shared.GameObjects.Components.Body.Behavior
+{
+    public abstract class SharedLungBehaviorComponent : MechanismBehaviorComponent
+    {
+        public override string Name => "Lung";
+
+        [ViewVariables] public abstract float Temperature { get; }
+
+        [ViewVariables] public abstract float Volume { get; }
+
+        [ViewVariables] public LungStatus Status { get; set; }
+
+        [ViewVariables] public float CycleDelay { get; set; }
+
+        public override void ExposeData(ObjectSerializer serializer)
+        {
+            base.ExposeData(serializer);
+
+            serializer.DataField(this, l => l.CycleDelay, "cycleDelay", 2);
+        }
+
+        public abstract void Inhale(float frameTime);
+
+        public abstract void Exhale(float frameTime);
+
+        public abstract void Gasp();
+    }
+
+    public enum LungStatus
+    {
+        None = 0,
+        Inhaling,
+        Exhaling
+    }
+}