NMSettingsConnectionInterface was created to allow the daemon and NM
clients to have common code that handled both system and user
connections. It's no longer needed now that user settings services are
gone.
This concludes the flattening of libnm-glib.
NMSettingsInterface was created to allow code to operate on a settings
service without caring about what kind of settings service it was. Now
that we have just one settings service, this is no longer needed.
More work needs to be done in order to handle errors and permission
settings in an appropriate manner.
In continuation of the theme, the removal of user settings services
means that the distinction between NMSysconfigConnection and
NMExportedConnection is no longer needed. Merge NMExportedConnection
into NMSysconfigConnection.
Much as with nm-remote-settings and nm-remote-settings-system, the
removal of user settings services means there is no more need for
separate interfaces for user and system settings services.
In libnm-glib, this commit merges everything in
nm-settings-system-interface into nm-settings-interface. Alongside with
that, we merge everything in the
org.freedesktop.NetworkManagerSettings.System DBus interface into
org.freedesktop.NetworkManagerSettings.
Originally, nm-remote-settings was used by the daemon to monitor the
user settings service, and its subclass nm-remote-settings-system was
used by NM clients to monitor the system settings service. With user
settings services gone, this distinction is no longer needed. Simplify
things a bit and merge the classes.