Possible workaround to move back to external ColladaLoader2

[T045T]

Back when we discussed the up_axis behavior of RViz / ros3djs, I opened https://github.com/mrdoob/three.js/issues/12888 asking for a convert_up_axis option like in previous releases.

Instead, the authors suggested using this code snippet:

new THREE.FileLoader().load( 'file.dae', function ( text ) {

    text = text.replace( '<up_axis>Z_UP</up_axis>', '<up_axis>Y_UP</up_axis>' );

    var collada = new THREE.ColladaLoader().parse( text );
    scene.add( collada.scene );

} );

https://github.com/mrdoob/three.js/issues/12888#issuecomment-359842246

I'm okay with keeping the embedded version, but if we want to move back to external ColladaLoader, this might be a solution :)