R1:bc718882491c

Mask typed passwords as they are entered into 'accountadmin'

Summary:
Currently, we echo the password as the user types it. This turns out to be a bit
of an issue in over-the-shoulder installs. Instead, disable tty echo while the
user is typing their password so nothing is shown (like how 'sudo' works).

Also show a better error message if the user chooses a duplicate email; without
testing for this we just throw a duplicate key exception when saving, which
isn't easy to understand. The other duplicate…