Tag groups with focus area(s)

[waded]

E.g. Joel Crane says Open Lab Idaho focuses on "3d printing, CNC milling, microcontrollers, and robotics."

Such information will be useful when gemstate.io is associating conversation to group, and for gemstate.io display of details about the group when we get to that.

I'd rather put this in gemstateio-groups so people can edit it themselves, rather than the agent doing it and hiding the information (the agent may edit gemstateio-groups eventually, but not soon.)