WIP: stream_mbox(): Add Archived-At header
The Archived-At header will point to the domain the MBox was downloaded from.
We still need the domain to be configurable according to #107.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
The Archived-At header will point to the domain the MBox was downloaded from.
We still need the domain to be configurable according to #107.