gsm: implement initial unlock dialog for PIN & PUK

[van Schelve <public van-schelve de>]

I found the new initial unlock dialog for PIN & PUK after testing the
latest git code today.

I have written a python based gtk application for pin handling some weeks
ago. The intention for this 
small app is that after a fresh system installation the user get's
prompted for the PIN until he has
entered it at least one time. Then I write the given PIN into a prepared
system-connection file and 
copy this to /etc/NetworkManager/system-connections. If the entered PIN is
wrong or the modem is 
locked I prompt either to reenter the right PIN or to enter the PUK
directly. It would be very nice
if the new pin dialog would have these features as well. At least it
should store the given PIN maybe
in gnome-keyring. Otherwise after each power off / on the user gets the
pin dialog again and again.

Best regards,
HG