Import listens from Foobar2000 playback statistics

[regorxxx]

This one is a bit more tricky. Currently foobar2000 stores play-count statistics for tracks, although no timestamps. Timestamps are available with foo_enhanced_playcount though.

Following the same rationale than my other enhancement proposal, it would be great to be able to export/sync Foobar2000 listens to ListenBrainz. i.e. those not already sent. In some cases users may have installed foo_listenbrainz2 at a later point, so many listens would be lost. This could fill the hole retroactively.

• Deduplication is required. Comparing the current listens JSON by the user against the local stamps. Since half the track must be listened to, it's more or less trivial to compute a match with JSON timestamp = local timestamp +/- half length (and the tags).
• Some tricks could be added here (like checking the plugin installation time, and only comparing listens before it). But I think it would be best to compare all values to ensure all values are synced on any use-case.
• This is thought as a sync option. i.e. will only add new values, and only if they are not already on the server. A one time action for most users.

[phw]

This only would make sense then if users have foo_enhanced_playcount installed.

This has absolutely no priority for me, but I would accept patches implementing this functionality.