cfdisk: supports also vertical menus

Signed-off-by: Karel Zak <kzak@redhat.com>
cfdisk: consolidate menu move code

Signed-off-by: Karel Zak <kzak@redhat.com>
cfdisk: add create lebel UI

Signed-off-by: Karel Zak <kzak@redhat.com>
cfdisk: menu actions refactoring

Signed-off-by: Karel Zak <kzak@redhat.com>
cfdisk: consolidate menu descriptions

Signed-off-by: Karel Zak <kzak@redhat.com>