Remove IActionBlocker.CanMove (#4449)

* Remove IActionBlocker.CanMove

Ported the remainders over to using MovementAttemptEvent which should also help make mob movement a bit faster.

* Make that check faster

Content.Client/Climbing/ClimbingSystem.cs

@@ -0,0 +1,9 @@
+using Content.Shared.Climbing;
+
+namespace Content.Client.Climbing
+{
+    public sealed class ClimbingSystem : SharedClimbSystem
+    {
+
+    }
+}