Actually the resource based code maintaining two pretty different
pages in one single class: The start page of the setup wizard and the
start page for the change datasource type wizard. Both dialogs looked
pretty different so to simplify the UI definition and to reduce number
of null pointers and branches in the underlaying code I've split
dbaui::OGeneralPage into two separate classes that share a few common
pieces.

Change-Id: I690e178992c528de112d91cecf00cc3c5156f1cf
Reviewed-on: https://gerrit.libreoffice.org/2887Reviewed-by: Petr Mladek <pmladek@suse.cz>
Tested-by: Petr Mladek <pmladek@suse.cz>