PNH charts use _configure_date_axis(), adjusted for default format override; remove unnecessary hh:nn from StartOfDayFilter - never need that accuracy; PNH chart checks again for plottable data in case regex failure (may generate empty chart)
adaptations for request form access by non-logged-in user * generate 'centre' token in login() for use in request-form url * adapt create_form_tokens() to accept 'centre' only * Local::Utils encrypt & decrypt functions capture Crypt::CBC errors & return empty not stacktrace
