GHSA-MX25-J3RC-6W2W Admidio's CSRF in registration `send_login` mode resets arbitrary user passwords

Summary modules/registration.php mode sendlogin regenerates a random password for useruuidassigned, stores its bcrypt hash in admusers.usrpassword, and emails the cleartext to that user. Every other state-changing mode in the same file assignmember, assignuser, deleteuser, createuser calls...