This commit adds a lot of files, but most of them have no impact on any
other code. The thrust here is to start creating chart pages showing
which tracks and artists were most played for various time periods. Lots
still not working, but we're getting there.
If you send Track data from the Jellyfin Webhook plugin, we'll do the
right thing with it. Lots more to do to clean this up, but it also
involved moduralizing the code for scrobbling so it's a little simpler
to understand what's going on.