Revert "Physics (#3452)"

This reverts commit 3e64fd56a1.

Content.Shared/Physics/FrictionController.cs

@@ -0,0 +1,24 @@
+#nullable enable
+using System;
+using Robust.Shared.IoC;
+using Robust.Shared.Physics;
+
+namespace Content.Shared.Physics
+{
+    public abstract class FrictionController : VirtualController
+    {
+        [Dependency] private readonly IPhysicsManager _physicsManager = default!;
+
+        public override void UpdateAfterProcessing()
+        {
+            base.UpdateAfterProcessing();
+
+            if (ControlledComponent != null && !_physicsManager.IsWeightless(ControlledComponent.Owner.Transform.Coordinates))
+            {
+                LinearVelocity *= 0.85f;
+                if (MathF.Abs(LinearVelocity.Length) < 1f)
+                    Stop();
+            }
+        }
+    }
+}