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

more stylistic changes

 - 1st webui, 2nd extensions-builtin, 3rd extensions
 - to load scripts independent of --data-dir
 - change load order key [x.basedir, x.filename, x.path] to [orderby(x.basedir), x.filename, x.path]

e.g., scripts/xyz_grid.py dependent extentions should loaded later
extensions\sd-webui-controlnet\scripts\xyz_grid_support.py
extensions\sd-webui-additional-networks\scripts\xyz_grid_support.py

 - 1st webui, 2nd extensions-builtin, 3rd extensions
 - to load scripts independent of --data-dir
 - change load order key [x.basedir, x.filename, x.path] to [orderby(x.basedir), x.filename, x.path]

e.g., scripts/xyz_grid.py dependent extentions should loaded later
extensions\sd-webui-controlnet\scripts\xyz_grid_support.py
extensions\sd-webui-additional-networks\scripts\xyz_grid_support.py

more stylistic changes

fix some style inconsistenices

allows for loading script params

rework #6329 to remove duplicate code and add prevent tab names for showing in ids for scripts that only exist on one tab

limit extension preload scripts to just one file named preload.py

do not mess with components' visibility for scripts; instead create group components and show/hide those; this will break scripts that create invisible components and rely on UI but the earlier i make this change the better