CE-2411: Add MOTD to IOC hosts

We would like to add a custom MOTD when users log onto IOC hosts. We're nice like that.

@andersharrisson this is a simpler MR than !23 (merged), but it is somewhat in conflict with it (this one assumes that iocs is a list of all IOCs on the host, which is in obvious conflict with that merge request); it might be better for this one to be merged first and then I can update !23 (merged) accordingly.