[cups] Provide password for CLI tools

[Stephan]

Michael,

I think we can pretty much easily implement most CUPS operations in our own
IPP client implementation, which can then use one of the HTTP
authentication mechanisms supported. However, there is one thing we can not
replace, that  is the IPP Everywhere printer creation. What would be of
help is a way to save a PPD for an IPP Everywhere printer. We could then
create a PPD locally and call CUPS-Add-Modify-Printer on the remote server.

How would you judge extending lpadmin so that it can save a PPD insted of
creating a queue for an IPP everywhere printer, or to provide a separate
tool that can do this?