kcm: Provide the driverless config option when driver discovery fails

CUPS documentation notes that just about every printer produced since 2009 is IPP Everywhere capable, so as is the case with normal driver discovery, let's add the option for "driverless" config if the driver discovery fails (this excludes Direct Connections ie. USB).

This also changes preferred driver recommendation to "exact-cmd" when available as this is actually a higher recommend than just "exact" per SCP.

Of note:

• Almost all modern printers are IPP capable
• Driverless should be preferred
• This makes it click-thru, same as if recommended driver options were found

Follow-on to !115 (merged)

Auto-discovery: Drivers NOT found