callback postprocess_image_after_composite

[w-e-w]

Description

new callback callback postprocess_image_after_composite
same as postprocess_image but after image = apply_overlay(image, p.paste_to, overlay_image)
this allows it to operate on the whole image as opposed to only the crop region when performing inpaint_full_res

inpaint_full_res aka inpaint area = only masked

background I got a issue post on one of my extensions

• Detect whole image when generating img2img  w-e-w/sd-webui-nudenet-nsfw-censor#9

because the image region that it can operate in postprocess_image is cropped, the extension performs suboptimally
so I decided to add this call back after the composite result

this callback could be used for the other extensions if they need to operate on the entire image or for whatever reason they need to operate after most other post-processing extentions

actual usage pending merge to my extensions assuming that this PR is acceptable

• apply censor after composite w-e-w/sd-webui-nudenet-nsfw-censor#10

---

I'm bad at naming postprocess_image_after_composite
if anyone has better name it can be changed

Checklist:

• I have read contributing wiki page
• I have performed a self-review of my own code
• My code follows the style guidelines
• My code passes tests