Refactor AI considerations (#1278)

Considerations are now instantiated under a manager and re-used between entities where they pass in their blackboard to get a score back.
Also makes the API a bit nicer to use.
Also some random cleanup.

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

Content.Server/AI/Utility/Considerations/Movement/DistanceCon.cs

@@ -1,4 +1,3 @@
-using Content.Server.AI.Utility.Curves;
 using Content.Server.AI.WorldState;
 using Content.Server.AI.WorldState.States;
 
@@ -6,9 +5,7 @@ namespace Content.Server.AI.Utility.Considerations.Movement
 {
     public sealed class DistanceCon : Consideration
     {
-        public DistanceCon(IResponseCurve curve) : base(curve) {}
-
-        public override float GetScore(Blackboard context)
+        protected override float GetScore(Blackboard context)
         {
             var self = context.GetState<SelfState>().GetValue();
             var target = context.GetState<TargetEntityState>().GetValue();