sdk: do not explicitly define Qt dependency packages

Until now, the toolchain used by CI has been created without Qt, but with
all (best guess) Qt dependencies. Now toolchain is created with Qt and we
get all Qt dependencies correctly into the toolchain. As a consequence,
CI will now need to build Qt, which has not been covered in CI before.

The difference between embedded-sdk and embedded-qt5-sdk is that
the former does not include files needed for debugging.

Change-Id: Ie2be156c07e51119c0d4782494d6bcde6f34ed60
Reviewed-by: Risto Avila <risto.avila@qt.io>