* [NOD-307] Implement API-Server GET /blocks
* [NOD-307] Implement API-Server GET /blocks
* [NOD-307] Add comments to exported constants
* [NOD-307] Flatten GET query values and check that 'order' value is valid
* [NOD-307] Validate order values in GetBlocksHandler
* [NOD-307] Add convertQueryParamToInt function
* [NOD-322] Make database.DB a function
* [NOD-322] Move context to be the first parameter in all functions
* [NOD-322] Set db to nil on database.Close()
* [NOD-322] Tidy go.mod/go.sum
* [NOD-322] Use http package const + message for StatusInternalServerError