FEATURE: Allow sending invites to staged users (PR #5512)

Could I get a second pair of :eyes: for this change please?

  • Allows inviting staged users
  • Forces staged users to activate their account (validate email) after accepting the invite
  • Moves the code that marks a user as from_staged during unstaging into the User class to make it reusable


You’ve signed the CLA, gschlager. Thank you! This pull request is ready for review.

Looks good to me. :+1: