binder: Add iface/network addition/removal callbacks

Add generic functions to invoke callbacks on all registered
|ISupplicantCallback|, |IIfaceCallback| & |INetworkCallback| objects.

Invoke callbacks to indicate:
1. Creation of new interfaces.
2. Removal of interfaces.
3. Addition of networks.
4. Removal of networks.

BUG: 30093041
Change-Id: I5e7c4a8470a3886b89c85d8851ae9f3cb7d5a820
TEST: Ran integration tests under wificond.
Signed-off-by: Roshan Pius <rpius@google.com>
4 files changed