There are various negative effects if these settings are allowed in the extra options for txt2img or img2img. This PR removes them from the extra_options lists at load time.
'sd_model_checkpoint' and 'CLIP_stop_at_last_layers' will invisibly override main UI settings, leading to confusing behaviour
'sd_vae' doesn't seem harmful, but can create an empty block in the UI section
'forge_additional_modules' causes an error that prevents the UI from loading
- correctly read values from pasted infotext
- setting for column count
- infotext paste: do not add a field to override settings if some other component is already handling it
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
