refactor: reorganize networking and data bridge scenes

* Move networking scenes under `controllers/networking`
* Move data bridge scene under `scenes/data`
* Rename the bridge node to `data_bridge`
* Update lobby UI scene path
* Remove unused lobby RPC node/script

scenes/data/game_state.gd

@@ -0,0 +1,57 @@
+class_name GameState extends Node
+
+
+@warning_ignore_start("unused_signal")
+signal update_cue_cam_position
+
+signal balls_stopped_moving
+signal white_ball_sunk
+signal white_ball_needs_hard_reset
+signal reload_scene
+signal process_ball
+signal reap_ball
+@warning_ignore_restore("unused_signal")
+
+
+func _init() -> void:
+	Globals.game_state = self
+
+func load_game_scene(scene_str: String) -> void:
+	var scene  = load(scene_str).instantiate()
+	var target = get_tree().root.get_node("billiards/scene")
+
+	target.add_child(scene)
+
+func set_game_scene(scene_str: String) -> void:
+	var scene   = load(scene_str).instantiate()
+	var target  = get_tree().root.get_node("billiards/scene")
+
+	if "game" in scene_str:
+		scene.name = "game"
+	elif "lobby" in scene_str:
+		scene.name = "lobby_screen"
+	elif "start" in scene_str:
+		scene.name = "start_screen"
+
+	clear_game_scene(target)
+
+	target.add_child(scene)
+
+func clear_game_scene(container: Node) -> void:
+	for child in container.get_children():
+		child.queue_free()
+
+	await get_tree().process_frame
+
+func switch_active_player() -> void:
+	# TODO: Move away from using client ID or mask it with a map ID
+	if Globals.multiplayer_data.current_turn_player_id == Globals.game_data.client1:
+		Globals.multiplayer_data.rpc(
+			"set_active_player_id",
+			Globals.game_data.client2
+		)
+	elif Globals.multiplayer_data.current_turn_player_id == Globals.game_data.client2:
+		Globals.multiplayer_data.rpc(
+			"set_active_player_id",
+			Globals.game_data.client1
+		)