Migrate from X.Org to Wayland

Closes #12213 (closed), #19042 (closed), #14623 (closed), #15635 (closed), #19008 (closed), #16795 (closed), #18020 (closed), #17284 (closed), #5422 (closed), #9767 (closed), #7502 (closed), #18339 (closed)

• intrigeri reviews the MR
• boyska provides input on !838 (comment 196874)
• intrigeri fixes the issues reported by his own review
  • code
  • test suite
• boyska reviews the diff between anonym's original MR (412c5b57) and intrigeri's changes
• Check Jenkins results