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/lyrics.js

@@ -1,5 +1,8 @@
 class Lyrics{
-	constructor(file, songOffset, div, parsed){
+	constructor(...args){
+		this.init(...args)
+	}
+	init(file, songOffset, div, parsed){
 		this.div = div
 		this.stroke = document.createElement("div")
 		this.stroke.classList.add("stroke")