Add Phila Historical Registry sites

[wheelmrk]

In a single layer under development by PCPC there's a combination of parcel polygons (or building footprints depending on what they decide) for individually designated buildings and larger historical district polygons. Add as a service area lookup to AIS and a result in Property.phila.gov but has to have disclaimer something like: "this address is found in the Phila Historical Register, please contact the Historical Commission for details (URL)."