Module qrinvite

Supporting code for the QR-code invite.

QR-codes are decoded into a more general-purpose Qr struct normally. This makes working with it rather hard, so here we have a wrapper type that specifically deals with Secure-Join QR-codes so that the Secure-Join code can have more guarantees when dealing with this.

Enums

• QrInvite
  Represents the data from a QR-code scan.