Add "New Database" button for Firebird file driver dialog.

Firebird is able to create new databases from within LO hence we need
to add a new property to database configration files.

This allows use of a db creation dialog (which is opened
by using the "New Database" button) in order to allow creating new
dialogs (in addition to being able to open existing databases using
the "Browse" button).

Conflicts:
	dbaccess/source/ui/dlg/ConnectionHelper.hxx

Change-Id: I6174f3b7d9032c48286b49b5ddf125cd3b428303