Bug fixing in sump pump project:  * Sending responses after action commands  * Adding now() time to debug response  * fixing long issues with self test time calculations  * Delaying water level measurement after test has ended to avoid interference  * Adding delay after self test to check if DC pump is ON due to induction triggering an alert  * Refactoring to move high/lows detection to pressure reading, instead of inferring from previous distance readings.
Also adding self test start call, and corresponding refactoring to separate it in its own function.