Load data from CA Proposition 65 chemicals list

[gtsueng]

California Office of Environmental Health Hazard Assessment maintains a list of chemicals known in the recognized in the state of California as causing cancer or reproductive harm. A list of these chemicals has been manually mirrored on Wikipedia, but can probably be automated by import into Wikidata.

The property proposal for a CA Prop 65 ID has been approved, and the data is currently in Mix N Match. Many of the ids can likely be automated via CAS-RN label matching.