web: Fix 'interfaceAdded'

by passing the correct data to the DBusInterface constructor.
agent: Don't omit standard interfaces with the fake ObjectManager.

We might actually want to use them.
web: Add 'changeProperties' method to DBusInterface.

So that we can use other sources of change notifications, such as
explicit GetAll calls or custom PropertiesChanged signals.
web: Directly talk to NetworkManager.
daemon: Remove networking API.
web: More documentation for DBusClient.