Custom SRP 2.2.0 Camera Textures

After introducing renderer lists we now introduce texture handles. We let the render graph manage the render textures for the color and depth attachments as well as their copies. While we adapt our passes to work with these we also decouple them from CameraRenderer. Shadow maps and post FX will also switch to this new approach in the future.

Custom SRP 2.2.0 (Catlikecoding)