ask-password: rework how we pass request meta info when asking passwords

ask-password: rework how we pass request meta info when asking passwords

Rather than adding more and more parameters to ask_password_auto(), let's
pass a structure of the fields that often are constant anyway.

This way, callers can fill in what they need, and we take the filled
structure which we can pass around internally as one.

This is in particular preparation for adding one more field in one of
the next commits.