Expose Baking Shader uniforms to the editor

[ozzr]

Currently you can get access to the main shader and the globalmap shader after locking the TerrainRenderer but the globalmap shader´s custom uniforms do not show in the editor

[ozzr]

I am experimenting with some alternatives to make the usage of this baking shader unnecessary by using the terrain shader itself. If experiments do not go well, I will implement this issue