Allow a way to send messages to the workers through the horde

[db0]

Add a way for Horde mods to forward a message to the worker. The worker would pick it as part of the pop, and would display it on their terminal for their user to see when they look next.

[tazlin]

I'd like to tack a request onto this a way to optionally send a message to the entire horde, workers of a particular kind (image/text/alchemy) or a list of workers.

[db0]

Ye that was the plan as well