Updates invidious instances and adds a note on README

[oliveiraleo]

As noted by other guys in this repository, some instances are down. I made some notes to give reasons to why to remove them to the pool of instances and highlighted some new public instances I've found to this date. Some related issues and PRs are here too to help managing all of them at once. At the end goes some instructions for those who want a workaround or a quick fix regarding invidious instances pool not working correctly.

• Not working
  https://invidious.xyz Off-line, HTTP 302 then 404
  https://invidiou.site Off-line, Domain for sale
  https://vid.mint.lgbt Shut down, HTTP 302 to https://redirect.invidious.io/
  https://invidious.site HTTP 302 to https://redirect.invidious.io/
  https://invidious.tube Off-line, Domain for sale
  https://invidious.silkky.cloud HTTP 404
  https://invidious.himiko.cloud HTTP 302 to an Ads website
  https://tube.incognet.io HTTP 302 to https://incogtube.com/ *
  https://invidious.048596.xyz HTTP 503 and certificate expired since 2021

* I left it out of my suggestions below because it says that it's a (kinda heavily) modded version (aka fork) of invidious project and I'm not sure if it's okay for this project to redirect to instances like this one

• Suggestions to add (my commits actually do that)
  https://inv.riverside.rocks
  https://invidious.osi.kr
  https://yt.artemislena.eu
  https://invidio.xamh.de
  https://invidious-us.kavin.rocks
  https://invidious.flokinet.to
  https://invidious.privacy.gd
  https://invidious.esmailelbob.xyz
  https://invidious.mutahar.rocks
  https://inv.bp.mutahar.rocks
  https://invidious.weblibre.org

• Some related issues e PRs
  update instances #374
  Remove invidiou.site #337
  Invidious.tube down. Youtube redirect dangerous #325
  Please add invidious-us.kavin.rocks to the invidious instance  #370
  Remove vid.mint.lgbt #341
  Many dead invidious instances #356

• Other references
  https://docs.invidious.io/instances/

• My working test env
  Mozilla Firefox Beta v99.0b8
  ZIP file generated accordingly with the instructions from README (unsigned, as it was just for testing purposes)

• Extra instructions
  If you found this post searching for instances to add or how to fix some instances, follow these steps below (for Firefox)
  -> Head to about:addons
  -> "Privacy Redirect" > "Preferences"
  -> Select the "Advanced" tab
  -> Click on "Invidious"
  -> On the first line that reads: "Invidious random instance pool", copy and paste the entire line below (you can override the content) which contains the old and new working instances

https://invidious.snopyta.org,https://invidious.kavin.rocks,https://tube.connect.cafe,https://invidious.zapashcanon.fr,https://yewtu.be,https://invidious.namazso.eu,https://vid.puffyan.us,https://dev.viewtube.io,https://inv.riverside.rocks,https://invidious.osi.kr,https://yt.artemislena.eu,https://invidio.xamh.de,https://invidious-us.kavin.rocks,https://invidious.flokinet.to,https://invidious.privacy.gd,https://invidious.esmailelbob.xyz,https://invidious.mutahar.rocks,https://inv.bp.mutahar.rocks,https://invidious.weblibre.org

PS: If you guys have any other working instances to suggest, please comment below and I'll try to update the comma separated list above.

Thanks for the author and the other contributors for this amazing extension.