Add APIs for discover/resolve on specific networks

Test that NsdManager specifies the correct network when a service is
discovered, and that services can be resolved on a specified network.
Also test that service discovery can be started on a specific network.

Bug: 190249673
Test: atest NsdManagerTest

Change-Id: Ie8b551ce9e33e3adf35f75508f91bbd0df71f837
4 files changed