[krbdev.mit.edu #7942] provide UI to remember default ticket lifetime/renew life

[Benjamin Kaduk via RT]

In the advanced "Get Ticket" window, we have sliders for the ticket lifetime and renewable 
lifetime.  However, these only affect the first ticket obtained (not even renewals of that ticket?), 
and there is no UI to set the default.
A registry value in {HKCU,HKLM}\Software\MIT\Leash32\lifetime and similar will set the default.

We could have a checkbox in the advanced get ticket view to remember the current settings as 
the defaults.  Maybe also a button to restore the original defaults.