ImportSongs: Add plugin support

- Files with filenames that end with .taikoweb.js can be imported and run to add custom functionality to the game
- The plugin file is a javascript module script that should have a class in the default export
- Currently supported methods in the class: name (string), load, start, stop, unload (functions)
- The class can be extended from the Patch class to add automatic patching of variables and functions
- Here are some of the plugins I made: https://github.com/KatieFrogs/taiko-web-plugins

public/src/js/game.js

@@ -1,5 +1,8 @@
 class Game{
-	constructor(controller, selectedSong, songData){
+	constructor(...args){
+		this.init(...args)
+	}
+	init(controller, selectedSong, songData){
 		this.controller = controller
 		this.selectedSong = selectedSong
 		this.songData = songData