replace busybox.tar binary by Makefile

[pmorjan]

This pr adds a Makefile to replace the binary integration-test/test_data/busbox.tar

The old busybox.tar also includes '/usr/bin/getconf' which is not part of busybox. I'm not sure if this is still needed. The new Makefile builds this a well. Could be removed if it's no longer needed.

[laijs]

would you try to remove '/usr/bin/getconf' and test?

[pmorjan]

looks good to me