Merge branch '783-force-stud-address' of github.com:hackerspace-ntnu/…

…website into 783-force-stud-address

* '783-force-stud-address' of github.com:hackerspace-ntnu/website:
  add union back
  change union type and edit test for empty mail
  updated skill missing email
  get emails from members without skill
  change to use converter when sending internal emails
  add convert stud email method