Export feature

[JPDSousa]

Allow Rookit to export data from the database as audio files.

Options

Users can export:

• Tracks: Export all selected tracks;
• Artists: Export all artist's tracks;
• Albums: Export all album's tracks;
• Playlists: Export all playlist's tracks

Export formats:

• Zip - The content is stored in a zip/gz/tar/rar file;
• Folder - The content is stored inside the selected filesystem, inside a dedicated folder;
• Single audio file - The content is written to a single audio file, where the connection between tracks can be parameterized (e.g fade in/out)
• Playlist File - (e.g. m3u) TBD
• Custom - Other export formats should be easily supported