[Feature request] Add hide password Two-Step verification

[d99kris]

This makes sense. I don't use that functionality myself so I never reflected over that it echoed the entered password on the terminal.

For reference - during the setup of a Telegram with two-factor authentication, the following password prompt should hide the entered password:

Enter authentication password:

[d99kris]

Dev notes: Can probably use something like this GetPass() implementation: https://github.com/d99kris/nmail/blob/master/src/util.cpp#L754