Progressbar

Hi, this is not a bug, but a feature request that makes experiences smoother when there are many big glbs.

There is a need for a progress bar for each glb model. There is a component named "https://github.com/gladeye/aframe-preloader-component" but it finds how many glb assets are downloaded. The issue is that I have 1 big asset and many small. I need a progress bar for the 130MB glb I have. The big glb can not be split since it is a big boat that travels on the sea.

Aframe 1.3

Best, and many congrats for the good work, Dimitrios Ververidis (jimver04)