rsx: Unify composite texture creation and management

[kd-11]

• Some texture accesses require image compositing steps to assemble the requested image from existing subresources. Handle all the common routines in a unified manner to avoid having one broken path (e.g mipmap gather not supporting bitcast operations)

Fixes #8229

[Xcedf]

Confirm it fixes the issue, but only for native res

Upscaled resolutions have some green overlay, similar to Naughty Dog MLAA when upscaled, looks like it's different issue

[kd-11]

Upscaling 'green' is because you cannot interpolate floats byte-wise so the result after scaling when bitcast to float becomes nonsense. You should be able to fix it using resolution scaling threshold normally, unless the pass generating the data is full-frame in which case there isn't anything we can do about it.