Expose custom properties on instanced objects/assets

When making props to be assets, you'd very often want a way to change the color of parts of it. But currently you have to get through the mess that's library overrides, by adding a library override to the instance and then the individual object. And a whole lot of stuff can easily go wrong in your files (which should also be improved)

Imagine in your asset, you tie a material color to a custom property on the collection, and have that custom property be exposed when you link it elsewhere, then you could easily change the color, or other stuff about asset