Option to disable notifications/unread indicators for new member joining messages (but still show them)

The default new member messages are useful to see who joins the server, but having a notification for them seems overkill at times (especially if they end up lurking and not posting much).

My proposal is for it to be like the desktop version of Slack, where joining messages show up in the channel but don't trigger the Unread indicator (or notification if you set notifications to "All messages"). Users could configure this in server notifications or global settings.