archive rhythmbox-devel list

Requested details

1. The list name: rhythmbox-devel
2. The rationale on why the mailing list should be archived (i.e project unmaintained): moved to GNOME discourse
3. Whether the list should be aliased to a specific other mailing list address: not required

Additional information

Please remember we only remove the list information, subscriptions and NOT the archives themselves which are kept around for historical reasons.

/cc @averi