rework extras tab to use script system

scripts/postprocessing_gfpgan.py

@@ -0,0 +1,33 @@
+from PIL import Image
+import numpy as np
+
+from modules import scripts_postprocessing, gfpgan_model
+import gradio as gr
+
+from modules.ui_components import FormRow
+
+
+class ScriptPostprocessingGfpGan(scripts_postprocessing.ScriptPostprocessing):
+    name = "GFPGAN"
+    order = 2000
+
+    def ui(self):
+        with FormRow():
+            gfpgan_visibility = gr.Slider(minimum=0.0, maximum=1.0, step=0.001, label="GFPGAN visibility", value=0, elem_id="extras_gfpgan_visibility")
+
+        return {
+            "gfpgan_visibility": gfpgan_visibility,
+        }
+
+    def process(self, pp: scripts_postprocessing.PostprocessedImage, gfpgan_visibility):
+        if gfpgan_visibility == 0:
+            return
+
+        restored_img = gfpgan_model.gfpgan_fix_faces(np.array(pp.image, dtype=np.uint8))
+        res = Image.fromarray(restored_img)
+
+        if gfpgan_visibility < 1.0:
+            res = Image.blend(pp.image, res, gfpgan_visibility)
+
+        pp.image = res
+        pp.info["GFPGAN visibility"] = round(gfpgan_visibility, 3)