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/Preset/BodyPresetPrototype.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Collections.Generic;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Serialization;
+using Robust.Shared.ViewVariables;
+using YamlDotNet.RepresentationModel;
+
+namespace Content.Shared.GameObjects.Components.Body.Preset
+{
+    /// <summary>
+    ///     Prototype for the BodyPreset class.
+    /// </summary>
+    [Prototype("bodyPreset")]
+    [Serializable, NetSerializable]
+    public class BodyPresetPrototype : IPrototype, IIndexedPrototype
+    {
+        private string _id;
+        private string _name;
+        private Dictionary<string, string> _partIDs;
+
+        [ViewVariables] public string ID => _id;
+
+        [ViewVariables] public string Name => _name;
+
+        [ViewVariables] public Dictionary<string, string> PartIDs => new Dictionary<string, string>(_partIDs);
+
+        public virtual void LoadFrom(YamlMappingNode mapping)
+        {
+            var serializer = YamlObjectSerializer.NewReader(mapping);
+            serializer.DataField(ref _id, "id", string.Empty);
+            serializer.DataField(ref _name, "name", string.Empty);
+            serializer.DataField(ref _partIDs, "partIDs", new Dictionary<string, string>());
+        }
+    }
+}