Make glideins advertise who is supposed to be managing them.

[vbrik]

We have a bunch of glideins that appear to be out of date and it's not clear who to contact about updating them. GLIDEIN_Site is a start, but not enough because it looks like at some sites multiple people run client.py.

An alternative would be to maintain information about all pyglidein admins, but keeping this info up-to-date will likely be a challenge.

Would be good to make this a required field in in client config.

Should this be a name? An email address? Both?