Add parental controls / safe mode

Description

This is a top-level tracking ticket for common parental controls.

1. Add support to disable destructive operations
2. Add support for ITUNESADVISORY / RTNG tag to display "E" for explicit language audio tracks
3. Add support to exclude explicit audio tracks and podcasts from playback/shuffle all
4. Add support for limiting audio volume separately for headsets (when connected) and built-in speakers