Prompt for challenge-response mode

[labuwx]

It would be great if yubico-pam could display a prompt (PAM_TEXT_INFO) in challenge-response mode too.
We should have the option to hide/show the prompt but by default PAM_SILENTshould be respected.
The prompt= flag from #206 should change this prompt too.

I use this pam with sudo and sometimes I cannot tell if my computer is still working on something or waiting for me to tap the key, e.g.: make && sudo make install.

[excalq]

Why not include support for cue and cue_prompt as https://github.com/Yubico/pam-u2f does?

[labuwx]

When I opened this issue, I did not not know about pam-u2f and cue.
However I simply switched over to pam-u2f after my custom yubico-pam build broke last November.