Bluetooth media player messaging

[aselafernando]

Created messaging from the Bluetooth media player. This will broadcast the current track details and track position so plugins can make use of this. This will allow writing this data to a vehicle display over CANBUS or serial etc.

[viktorgino]

I think it'd be a better idea to a media position and media info changed signal to MediaInterface, so all the other media plugins can use it.
Then MediaManager could handle sending it onto the messaging bus etc

[aselafernando]

Yep that makes sense, I have modifed the code so now MediaManager is the interface to the message bus.

MediaManager::mediaPosition quint32 and MediaManager::mediaTrack QVariantMap are the two messages. Just tested this and it worked well. Could probably drop "media" from the id as well.

[aselafernando]

I changed the messages to MediaInput::position quint32 and MediaInput::track QVariantMap to be more consistent with the existing