Description:

A config option to allow admins to get and set the mailbox owner's \Seen flags.


Documentation:

There are no documentation changes


Config changes:

There is a new boolean option: `admins_get_internal_seen` - which, if set,
means that admins always get and set the same \Seen flags as the mailbox owner.


Upgrade instructions:

If setting admins_get_internal_seen to true, ensure that any tools which access
he user's mailbox as an admin are updated to use EXAMINE or FETCH .SILENT to avoid
changing \Seen flags for the mailbox owner unexpectedly.


GitHub issue:

None
