Split entity management from entity queries (#1665)

* Split entity lookups from entitymanager

* Helps if you subscribe dingus

* Handle map changes

* Stacks instead

* Make mapchanges use a queue because it's probably better

Moves likely only care about the latest position

* IoC what you did there

* IoC refactor

* Minor optimisations

* Apply feedback

* My IQ dropped 3 sizes that day

* Rest of acruid's feedback

* final_no_actual commit

* enlightenment?

* Liftoff

* final_commit_v2_actual

Co-authored-by: Metal Gear Sloth <metalgearsloth@gmail.com>

Robust.Server/GameObjects/ServerEntityManager.cs

@@ -79,8 +79,8 @@ namespace Robust.Server.GameObjects
         /// <inheritdoc />
         public override void Startup()
         {
-            base.Startup();
             EntitySystemManager.Initialize();
+            base.Startup();
             Started = true;
         }