Allow a QSG*Node to render into a QSGTexture

I would want a Geometry Node / Material / Material Shader to render into a texture (texture render target).

My usecase is that I want shader-based blending effects between several nodes within one QuickItem. In addition it would be nice to provide a shared texture to render into and to have the ability to let several nodes render into this one texture (i.e. creating a texture atlas).

As well as allowing to create layered QSGTextures that can be reused by several nodes.

You can do such things with using the private QRhi Framework.