Player Statistics

[maxjoehnk]

Add statistics for each entity:

• play count
• skip count

Statistics for player usage? usual play times?

Do we want this in core?
It could be implemented as an extension but access by other extensions could be harder.
Storage in metadata section?
We could expose a basic api to access statistics from the extension.
Should we import statistics from e.g. Google Play Music?

impl StatisticExtension {
 pub fn get_track_play_count(track: &Track) -> Option<usize>;
 pub fn get_track_skip_count(track: &Track) -> Option<usize>;
 ...