Add showing of the last water interval trigger for the interval
triggers. Auto refresh overview screen every second if it is showing.
Small update of the interval trigger configuration
Cache the current time from main to ease calculations later, this way we
only need to handle wrapping of millis() for open ports in main
Change how we handle open ports. Set an open time and a duration. We
need this handle wrapping the millis() when we have an open port. It is
also cleaner this way
Main loop handler for opening or closing ports based upon interval
timer.