Configurable password prompt

[clach04]

Internally password prompt is configurable via API.

#28

#77

Need more API implementations. For example externally password prompting toolkits like:

• ✔️ getpass - text, tested in ptcipher (TODO check/test ptig, ptcat, ptgrep)
• ✔️ tk - tkinter, tested in ptcipher (TODO check/test ptig, ptcat, ptgrep)
• Windows GUI password prompt support #71
• https://github.com/ponty/psidialogs - NOTE no password support, does have string prompt support
• gpg pinentry, also see age passphrase encryption #49
• pinentry
  • https://github.com/wking/pyassuan
• askpass SSH_ASKPASS, tty_askpass, GIT_ASKPASS os environment variable for password returning tool #77
  • https://github.com/r-lib/askpass/blob/main/src/win32/win-askpass.c
  • ssh-askpass
  • update-alternatives --list ssh-askpass
  • https://sourceforge.net/projects/winsshaskpass/
  • git-askpass, as shipped in git for Windows, "C:\Program Files\Git\mingw64\bin\git-askpass.exe"
• Zenity - https://en.wikipedia.org/wiki/Zenity
• dialog - https://invisible-island.net/dialog/
  • Python wrapper https://pythondialog.sourceforge.io/
  • cdialog
  • Xdialog - http://xdialog.free.fr/
  • lxdialog
  • https://invisible-island.net/cdk/cdk.html
• alternative password entry samples #28