Refactor endpoints

This will break all functionality with the old code. New code also needs to be updated to reflect changes. 

new endpoints: 
hmda/volume/34.234512/-117.597656/34.161818/-117.685546/90000451965/1,2,3/
/census/race_summary/34.234512/-117.597656/34.161818/-117.685546/

combined: 
/api/all/34.234512/-117.597656/34.161818/-117.685546/90000451965/1,2,3/