* Harmonize DateTimePicker styling with each theme palette
The jQuery UI datepicker and timepicker addon rendered with the stock ThemeRoller texture-image backgrounds and a generic gray/green look that did not match any theme (most visible in the deepness dark theme). Add per-theme, picker-scoped overrides to every theme's jquery.timepicker.css so the popup surface, header, weekday labels, day cells, selected/hover/today states, Now/Done buttons, and the time sliders use each theme's own accent and content colors. Rules are scoped to .ui-datepicker so other jQuery UI widgets are unaffected.
* Address DateTimePicker a11y review (develop)
- Reset the nav-icon filter on prev/next hover (cacti, paw, raspberry) so the dark jQuery UI sprite stays visible on the pale hover tint.
- Give carrot and hollyberry a dark header title + dark nav icons so the month/year text clears AA on the light-ish accent header.
- Carrot: move to the theme's darker orange (#d2691e) for the today outline and sliders, and use a dark foreground on the orange selected-day/button fills.
- cacti and hollyberry: dark foreground on the accent selected-day/button fills to clear 4.5:1.
- paper-plane and sunrise: invert the icon sprite to white so the arrows are visible on their dark headers.
- dark and modern: add an explicit focus outline on the time-slider handles (both themes suppress the browser outline globally).
- midwinter: rebuild the override on the theme palette variables so the picker follows dark/light mode, with the theme blue as a fixed AA accent.
- Update FontAwesome to v5.8
- Add some new themes
- Allow dynamic theme selection via newtheme parameter (newtheme=carrot)
- Fix up some Auth dialog issues
TheWitness