MVP a manually updated TTS Service field

Here's the idea: I create and maintain a very simple list (txt or csv file in github, that is one column, just the exact target URLs). Our Site Scanning engine ingests that list and for the exact matching target URLs in our database, would mark a new field named `api.data.gov` TRUE. Otherwise, the field would be FALSE.

Start by locating the Site Scanning engine's list-ingestion entry point and the database schema for scan results. Confirm how exact target URL matches are represented, then define the manually maintained one-column TXT or CSV input and the `api.data.gov` boolean field. Done means matching URLs are TRUE and all other URLs are FALSE.

Written by the indexing model from the issue text.