1. Log request uri in server request handler for log level debug.
I prefer to log this level info in mny fork because it enables quick
diagnosis when my Alexa speech skill has misheard what I said. But
doing it on debug level is more consistent with the original program.

2. Add /loglevel get request which implements ability to
change the process NODE_LOG_LEVEL (one of trace, debug,
info, warn, or error (and off which is a synonym for error)).
Document the command in static doc content.

This is very useful when the code is running in a container. Especially
if you add it to your alexa skill as I have.

add apple music playlist support

fix: use correct variable for shuffle response