git sync functionality

[mipmip]

• research which git lib we should use
• how shall we deal with git conflicts? In app simple resolving..
• sync settings view:
  • generate or store ed25519 private
  • copy public key (generated from private)
  • remote git url
  • link to instructions for deploykey
  • auto sync? boolean
• backend:
  • auto commit: generate smart messages
  • auto git sync