40C3: tours, schedule data, tour map and calendar entries

- tour-map shortcode: Leaflet map of the tour locations with routes from the
  Congress, from the map/tours sections of data/schedule/<event>.yaml; Leaflet
  and the OSMIC, Maki and Temaki icon sets vendored; 39C3 uMap data converted.
- calendar shortcode: per tour date, a pill with an .ics download (iCalendar)
  and a Google Calendar link; Font Awesome Free vendored, fa-icon partial.
- README sections for the calendar and tour map shortcodes and the map data.

assets/vendor/icons/maki/shop.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg height="15" viewBox="0 0 15 15" width="15" xmlns="http://www.w3.org/2000/svg" id="shop">
+  <path d="m13.33 5h-1.83l-.39-2.33c-.1601-.7182-.7017-1.2905-1.41-1.49-.3493-.1124-.7131-.173-1.08-.18h-2.24c-.3669.007-.7307.0676-1.08.18-.7083.1995-1.2499.7718-1.41 1.49l-.39 2.33h-1.83c-.2761-.0017-.5013.2208-.503.497-.0003.0519.0074.1035.023.153l1.88 6.3c.1964.6246.7753 1.0496 1.43 1.05h6c.651-.0047 1.2247-.4289 1.42-1.05l1.88-6.3c.0829-.2634-.0635-.5441-.3269-.627-.0463-.0146-.0945-.0223-.1431-.023zm-8.81 0 .36-2.17c.0807-.3625.3736-.6395.74-.7.2463-.0776.5019-.1213.76-.13h2.24c.2614.0078.5205.0515.77.13.3664.0605.6593.3375.74.7l.35 2.17h-6z"/>
+</svg>