Tile friction ECS (#8012)

* Tile friction ECS

Removes some resolves which is really nice.

* Velocity checks

Content.Shared/Friction/TileFrictionModifier.cs

@@ -1,55 +1,14 @@
-using System;
-using Robust.Shared.GameObjects;
-using Robust.Shared.Maths;
-using Robust.Shared.Players;
-using Robust.Shared.Serialization;
-using Robust.Shared.Serialization.Manager.Attributes;
-using Robust.Shared.ViewVariables;
-
 namespace Content.Shared.Friction
 {
     [RegisterComponent]
+    [Friend(typeof(SharedTileFrictionController))]
     public sealed class TileFrictionModifierComponent : Component
     {
         /// <summary>
         ///     Multiply the tilefriction cvar by this to get the body's actual tilefriction.
         /// </summary>
         [ViewVariables(VVAccess.ReadWrite)]
-        public float Modifier
-        {
-            get => _modifier;
-            set
-            {
-                if (MathHelper.CloseToPercent(_modifier, value)) return;
-
-                _modifier = value;
-            }
-        }
-
         [DataField("modifier")]
-        private float _modifier = 1.0f;
-
-        public override ComponentState GetComponentState()
-        {
-            return new TileFrictionComponentState(_modifier);
-        }
-
-        public override void HandleComponentState(ComponentState? curState, ComponentState? nextState)
-        {
-            base.HandleComponentState(curState, nextState);
-            if (curState is not TileFrictionComponentState tileState) return;
-            _modifier = tileState.Modifier;
-        }
-
-        [NetSerializable, Serializable]
-        private sealed class TileFrictionComponentState : ComponentState
-        {
-            public float Modifier;
-
-            public TileFrictionComponentState(float modifier)
-            {
-                Modifier = modifier;
-            }
-        }
+        public float Modifier;
     }
 }