0.20.22 - Anticitizen One (hotfix #3)

Another smaller hotfix to address some outstanding issues before my Christmas break:

• Re-enabled selective downloading (SDL) on macOS and added definintion files for macOS to the API
• Fixed repair when the installed manifest is unavailable for some reason (#380)
• Fixed cleanup command which was broken after adding macOS support
• Disabled semi-automatic Origin activation on Linux (for now) and show instructions for manual process instead
• Added external_activation to info command output to note if a game requires activation via Origin or Uplay

Also check out the previous 0.20.19 release and 0.20.20/21 hotfixes:

• https://github.com/derrod/legendary/releases/tag/0.20.21
• https://github.com/derrod/legendary/releases/tag/0.20.20
• https://github.com/derrod/legendary/releases/tag/0.20.19