Separate part management from the rest of body manager component (#2017)

* Separate part management from the rest of body manager component

* Component reference

* Move more methods over

* Fix docs and move over BodyPreset

* Fix up body preset

* Create initialize method and remove constructor for BodyPreset

* Do the same for BodyTemplate and add Initialized properties

* Fix BodyTemplate HashCode test

* BodyTemplate test PLS

Content.Server/Body/Surgery/BiologicalSurgeryData.cs

@@ -243,7 +243,7 @@ namespace Content.Server.Body.Surgery
             performer.PopupMessage(Loc.GetString("Saw off the limb!"));
 
             // TODO do_after: Delay
-            bmTarget.DisconnectBodyPart(Parent, true);
+            bmTarget.RemovePart(Parent, true);
         }
     }
 }