Rewrite KGpg first start wizard to use KAssistantDialog instead of Q3Wizard

This also improves the assistant in several ways:
-allows to search for gpg binary if it is not in path
-improve searching for GnuPG config file
-ask GnuPG for config file before guessing it's location
-checks for the newer version first if both are present
-add quirk for Windows location of config file
-adds summary page at end of assistant
-allows user to choose if key generation dialog should be started or not
-when the default key is set in assistant save full fingerprint instead of only last 8 byte

By the way: the GUI stuff was more or less copied from the UIC generated file.
If anyone has improvements feel free to commit it or mail me a patch.