ADD rudementary main menu, needs refinement

states/game_state.py

@@ -0,0 +1,13 @@
+class GameState:
+    def __init__(self, switch_state_callback, screen):
+        self.switch_state = switch_state_callback
+        self.screen = screen
+
+    def handle_events(self, events):
+        pass
+
+    def update(self):
+        pass
+
+    def draw(self):
+        pass