List contacts through DBus

[exquo]

Contacts with private phone numbers (for whom only the UUID is known) are not shown when listContacts is run with --dbus flag. Nor when calling the listNumbers DBus method directly (through e.g. dbus-send). The listIdentities (both the dbus method and the CLI subcommand) return non-contact entries among its output (e.g. members of the groups that I am a member of, but who are not in my contacts and with whom I don't have 1-on-1 chats). Is there a way to get a list of contacts over DBus?

[AsamK]

Related: #1187