Add option to align with sgm repo's sampling implementation

Add missing infotext for RNG in options

unperdictable -> unpredictable

add VAE from main model into infotext, not from refiner model
option to make scripts UI without gr.Group
fix inconsistencies with refiner when usings samplers that do more denoising than steps

face restoration and tiling moved to settings - use "Options in main UI" setting if you want them back

split shared.py into multiple files; should resolve all circular reference import errors related to shared.py

- 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

- the setting for preferring opts.sd_vae has been inverted and reworded
- resolve_vae function made easier to read and now returns an object rather than a tuple
- if the checkbox for overriding per-model preferences is checked, opts.sd_vae overrides checkpoint user metadata
- changing VAE in user metadata  for currently loaded model immediately applies the selection