Add more db indexes

Adds indexes to:
* geo.state
* geo.state + county
* hmda.action_taken (for filtering)
* hmda.state + county (not currently used, but seems like it will be in the future)
* hmda.state + county + lender
* hmda.state + county + lender + action

Removes an index from hmda.county. We'd only ever need county in combination with state.