add an option to show selected setting in main txt2img/img2img UI

split some code from ui.py into ui_settings.py ui_gradio_edxtensions.py
add before_process callback for scripts
add ability for alwayson scripts to specify section and let user reorder those sections

modules/shared_items.py

@@ -55,5 +55,15 @@ ui_reorder_categories_builtin_items = [
 
 
 def ui_reorder_categories():
+    from modules import scripts
+
     yield from ui_reorder_categories_builtin_items
+
+    sections = {}
+    for script in scripts.scripts_txt2img.scripts + scripts.scripts_img2img.scripts:
+        if isinstance(script.section, str):
+            sections[script.section] = 1
+
+    yield from sections
+
     yield "scripts"