setting up terbium, eqiad hume-ish host

this also meant parameterizing all of the misc:maint classes. they
should default to the primary_site. for now, they are all set
explicitly, as we are not using terbium yet.

the ability to set explicitly will also be helpful if the maint
host in the primary site dies.

Change-Id: Iffd8a7cd2fa72705ab4a02ad57b7589e2f8c2d02
Merge "setting up terbium, eqiad hume-ish host" into production