RemoteActionGroup

The GRemoteActionGroup interface is implemented by ActionGroup instances that either transmit action invocations to other processes or receive action invocations in the local process from other processes.

The interface has `_full` variants of the two methods on ActionGroup used to activate actions: activate_action and change_action_state. These variants allow a "platform data" Variant to be specified: a dictionary providing context for the action invocation (for example: timestamps, startup notification IDs, etc).

DBusActionGroup implements RemoteActionGroup. This provides a mechanism to send platform data for action invocations over D-Bus.

Additionally, export_action_group will check if the exported ActionGroup implements RemoteActionGroup and use the `_full` variants of the calls if available. This provides a mechanism by which to receive platform data for action invocations that arrive by way of D-Bus.