Minimal set for CDN

[Utopiah]

Thanks to https://github.com/aframevr/aframe/pull/5333 now in 1.5.0 it's possible to define the CDN that can thus be local, thus follow https://github.com/aframevr/aframe/issues/5119 .

It's possible to clone this repository and point to the hosted version but this repository is huge (>500Mo). Briefly skimmed through it seems most of it (e.g .git itself, .blend model source, etc) aren't actually needed.

Few paths to consider, from easiest to more demanding

1. updating README.md with required directories, e.g ./fonts and ./controllers I imagine, clarifying which files can removed to trim down to lowest size
2. provide a "build" with the minimum, e.g a .zip generated from a script like tar -cvf minglb.tar fonts/ $( find controllers/ -type f -name "*.glb" )
3. changing the structure to have a dedicated directory with only necessary content, e.g ./required/ with ./required/fonts and ./required/controllers and keeping there only used files, e.g .glb but not .blend
4. splitting in 2 repositories