Add the ability to make smart playlists

[jverkoey]

This workflow would ideally be a superset of the iTunes/Apple Music smart playlist editor UX. Specifically, this includes the following features:

• [ ] Matching to [all|any] rule[s].
• [ ] Matching to one or more rule[s].
• [ ] <#Text field#> [contains|does not contain|is|is not|begins with|ends with] "string"
• [ ] <#Integer field#> [is|is not|is|is greater than|is less than|is in the range] "integer"
• [ ] <#Boolean field#> [is true|is false]
• [ ] <#Date field#> [is|is not|is|is after|is before|in the last|not in the last|is in the range] "date"
• [ ] Limit to X [minutes|hours|MB|GB|items] selected by [random|field}
• [ ] Live updating.

Live updating can likely happen any time the playlist is accessed (such as when viewing a playlist or exporting the library).