Fixes, clean-up, container management refactoring

. added dedicated container management commands:
.. add / remove / list / query / drain / calibration
. fixed mutually exclusive commands and / or shared resources
. fixed water level validation before using actuators
. removed UV device control
. removed flow meter device dependency in the system
. added dehumidifier (DH) control
. updated web UI to reflect DH device
. updated crontab.txt with new commands