Make EditorXR as a package

[blakedgross]

For consuming EditorXR it would be useful if it was addable via Unity Package Manager, whether as a github feed or as an official Unity package

[mtschoen-unity]

Thanks for your feedback! We completely agree, and in fact are in the process of doing this.

[JashanChittesh]

Very awesome! This will also make it much easier to use it from other packages / in a "package-i-fied project" ;-)