Stable Build

• Logging in and out with firebase.
• Signs in with anonymous account and will convert it.
• possible to signout.
  ✔ Upon closing the app and reopening it, data should be persistant @created(03-07-19 12:33) @done(03-12-19 16:06)
  ✔ When deleting the app and reinstalling it, data should be gone @created(03-07-19 12:33) @done(03-12-19 16:06)
  ✔ Data is not accessible from other devices @created(03-07-19 12:34) @done(03-12-19 16:06)