(WIP) Allow excluding non public only videos per source (member only)

[phyzical]

closes https://github.com/kieraneglin/pinchflat/issues/588 closes https://github.com/kieraneglin/pinchflat/issues/648

What's new?

• Adds logic to extract a videos "public" status via availaiblty = "public" this for the most part reflects member only videos.
  • will need to review this as it might also filter other videos some may want like unlisted (can pivot the naming if thats the case)
• adds a new option per source member_content_behviour was replicated via the short_form_behaviour and live_behaviour logic for profile

Any other comments?

Still need to look into if this is good enough or it will remove videos some may want, (personally i wouldnt mind skipping unavailable videos too) so can rename this to like "public_videos" if we prefer

Also need to update the index so need to mind the syntax to alter at

• [x] I am the original author of this code and I am giving it freely to the community and Pinchflat project maintainers

i know you said you were pondering how to solve this. so figured i would start in a direction to get the ball rolling