Implement location endpoints

[andyhaskell]

These endpoints in ClimaCell are for defining locations that can be referenced with a location_id. The endpoints include GET endpoints to list all locations or individual locations, a POST endpoint to create a new location, a PUT endpoint to update a location, and a DELETE endpoint to delete a location.

The steps to this should be:

• Define Go structs for the location request and response payloads, add serialization/deserialization test coverage
• Implement the GET endpoints as Client methods
• Implement the POST endpoint as a Client method
• Implement the PUT endpoint as a Client method
• Implement the DELETE endpoint as a Client method

https://developer.climacell.co/v3/reference#get-locations