Restrict search to dataset boundaries

[Leland]

Follow up to #33, this is a site whose address searching is constrained to the datasets' boundaries – in essence, if an address is provided which is outside of Chicago, there probably ought to be an error.

This would also need to be extended to the "find me" feature.

[derekeder]

in cartodb_lib.js we append chicago to all searches if it is not typed in. this seems to handle most cases: https://github.com/datamade/second-city-zoning/blob/main/js/cartodb_lib.js#L7

i think back when i wrote this code (about 10 years ago) i tried configuring the scope with Google Places Autocomplete but couldn't get it to work. open to other suggestions though!