Add prefix property to asset registry
Add prefix property to asset registry

Prefix is used in all URLs when loading assets.

playcanvas/engine,MicroWorldwide/PlayCanvas,sereepap2029/playcanvas,shinate/engine,guycalledfrank/engine,aidinabedi/playcanvas-engine,sereepap2029/playcanvas,shinate/engine,H1Gdev/engine,aidinabedi/playcanvas-engine,sereepap2029/playcanvas,MicroWorldwide/PlayCanvas,shinate/engine,H1Gdev/engine,guycalledfrank/engine,playcanvas/engine