Renewable pipeline for DHCR rent stabilization data

[wstlabs]

We managed to get rent stabilization data integrated into the demo version of the app, using a one-time snapshot 2015 FOIA request data:

https://github.com/clhenrick/dhcr-rent-stabilized-data

The goal is to get a renewable pipeline moving forward. It can use FOIA requests or other means, but ideally we should be able to refresh once or twice a year with minimal addition effort.

As with any pipeline, some basic safeguards should be in place to make sure the data are (if at all possible) basically compatible from one refresh to the next, and not substantially deteriorated (e.g. we should immediately be able to tell if we we get botched data set that suddenly has only half the rows as the previous instance).