Fix scripts load order

 - 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