This repo and the NPM package are out of date and no longer needed

Hello 😁 Just your friendly neighbourhood three.js dev dropping by.

This repo and the [associated NPM package](https://www.npmjs.com/package/three-collada-loader)are out of date and obsolete, since [the official three.js NPM package](https://www.npmjs.com/package/three) now contains the up to date `ColladaLoader`, both as a standard script file and as an ES6 module.

There are several out of date forks of three.js loaders around, and they frequently cause confusion for new users. Here's [the latest confused person](https://discourse.threejs.org/t/importing-a-collada-model-with-multiple-materials/8003). Will you help us by removing your outdated loader and NPM package?