Improved fault tolerance

Fixed bug which was causing an error reading the cooling threshold temperature
Added option to have zones adjust master temp when required - this is now the default behaviour
Improved error handling for network and API service outages. Plugin will continue operating and will re-establish communication when fault clears
Added soft refresh of device state every few seconds to improve responsiveness and accuracy of HomeKit device state
Reduced debug log verbosity when updating device state to only show essential details
Removed unnecessary .env dependancy used during initial development but no longer implemented