Customizable tokens for authenticated audiences members (3)

Currently, the tokens for authenticated audience members cannot be changed. It would be nice to let the organizer choose the token. Related to #13 (closed).

Change existing modal to have token changeable (not read-only) (1).
Change back-end to save the changed token (1).
Make sure that the accepted tokens are unique and limited to /[A-Za-z0-9\-]{3,255}/ (1)

Edited Jul 19, 2018 by Deleted user

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information