Integrate public facility dataset

The scripts to integrate the public facilities dataset are ready to go.

@hupili, can you run this on the backend after merging into master?

You need to first move the geojson file that @2blam put on the share drive (`hk_pub_facility/geojson/all_pub_facility_with_CACODE.json`), into the `scripts/data` folder as `pub_facility_cacode.geo.json`

Then, open up a python shell in scripts, and import `public_facilities`.  Run `public_facilities.main()` and it will append the necessary datapoints and translations to all the files.

fixes #9