[Cooker] PLease, add explicit time config step back to installer

[Borsenkow Andrej]

The "keep time in GMT" and "NTP sync" are too hidden. I only
accidentally discovered that installer wanted to keep my time in GMT
(because I had to install in English and then correct timezone). Most
people would not even know such options exist because install summary
would show correct value and they won't need to modify time settings.

There was explicit step in installer before (7.2 I guess). Please, add
it back.

-andrej