As pointed by https://github.com/cloudius-systems/osv/issues/119

 mgmt
should not be placed under module/mgmt but mgmt should be treated as a
module.

The config.json will now point to mgmt and the Makefile under mgmt will
take care of running the gradle

Signed-off-by: Amnon Heiman <amnon@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>