Make stopping and resuming of injection automatic when recording input.

[sabudum]

When pressing the 'Record' button while an injection is currently running, it should stop automatically, and once the recording is finished, injection should auto-start automatically.

This can be done in the inputremapper/gui/controller.py class and the start_key_recording(self) function, as such: I've created comments for new lines and removed some lines that would not be needed anymore.

    def start_key_recording(self):
        """Record the input of the active_group

        Updates the active_mapping.input_combination with the recorded events.
        """
        state = self.data_manager.get_state()
        if state == InjectorState.RUNNING or state == InjectorState.STARTING:
            # Store current running preset in a variable (previous_preset)
            # Stop injection
        # else:
            # Set previous_preset variable to null

        logger.debug("Recording Keys")

        def on_recording_finished(_):
            self.message_broker.unsubscribe(on_recording_finished)
            self.message_broker.unsubscribe(self._on_combination_recorded)
            self.gui.connect_shortcuts()
	    # If previous_preset variable is assigned:
                # Start injection of previous preset

        self.gui.disconnect_shortcuts()
        self.message_broker.subscribe(
            MessageType.combination_recorded,
            self._on_combination_recorded,
        )
        self.message_broker.subscribe(
            MessageType.recording_finished, on_recording_finished
        )
        self.data_manager.start_combination_recording()

Now, I've tried doing this myself, but the last time I tried cloning the repo and compiling the source, I completely destroyed my Linux installation and couldn't find the cause and revert my damage, had to reinstall everything, this is why I've created this issue.