added enemy state machine with idle, stunned, and dead states

scripts/State.gd

@@ -0,0 +1,16 @@
+extends Node
+class_name State
+
+signal Transitioned
+
+func Enter():
+	pass
+
+func Exit():
+	pass
+
+func Update(_delta : float):
+	pass
+
+func Physics_Update(_delta : float):
+	pass