Implement naive BMM streak counting for bible study

[sifferhans]

• investigate if we can access the npaw calculation in flutter
  not realtime, so not really relevant
• Use updateProgress method in BccmPlaybackListener for a naive but functional implementation.
• send to /Statistics/watched if listened > 50% and it hasn't been sent for the episode before
  • only send 2x per episode; first when going over 50%, and last when video playback is finished
• figure out how we map track id
  we will send the episode UUID to BMM, which has the episode -> track mapping
• if user is offline when request is sent, save it locally and try again at next app start
  • Strictly necessary?

to be implemented locally, only on mobile for now

Pull request here

[sifferhans]

PR: #523

[sifferhans]

I've updated the updateProgress hook in BccmPlaybackListener to also pass along the total duration of the currently playing media item, so we can calculate the percentage played

I need the BMM endpoint to continue with this task