Create a handler to get results

route: GET `/results/:chain_id/:round_id/:algorithm`

* find the record in the results table by chainId, roundId, algoithm
* return 404 if not found
* if found, return the timestamp + the field url in a json object
* add a status field based on the timesstamps (`generated_at`, `last_requested_at`)
* pending
* running
* done

notes:

in the next tickets we will:
* validate if the round chainId/roundId exists
* check if a calculation already exists and redirect to its GET route