modules: include apps.git as module repository

This way there is no longer need for apps.git/modules.json. That file
currently holds zero information. It has no other purpose than being
source of merge conflicts.

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
modules: configure osv.git/modules as module repository

Signed-off-by: Tomasz Grabiec <tgrabiec@cloudius-systems.com>
Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>