password prompt implementation in BEAM

[max-au]

CLI tools do not have a good way to request a password.
Existing solution is to quickly type backspace key when entering passwords, but it does not work when password is pasted (or typed faster than 100 characters per second)

[max-au]

erlang/otp#4337

[starbelly]

Let me add a few comments on this :

• The original issue I created on OTP is around stty, while that's nice to have, it doesn't work on windows and possibly some other platforms. That should be noted. Thus, even if that problem is fixed (which is should be regardless, sans something be dumb in the example code) it surely should be, but it's not universal. Of course one could hack on the tty driver for windows perhaps, but eh...

• I made an attempt to carry over the get_password implmenetation from group.erl into user_drv.erl but I could not get it to work. Every way I tried resulted in an VM crash per blocking. The models are completely different, yet I still feel like there should be a way to get this to work. The implementation in group.erl works quite well, not so hacky like what we have in rebar3_hex and mix/hex.