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/temaki/striped_zone.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg viewBox="0 0 15 15" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <path d="M10.5 8.92L10.5 6.65L4.5 10.08L4.5 12.35L10.5 8.92L10.5 8.92ZM10.5 10.65L5.51 13.5L10.5 13.5L10.5 10.65ZM10.5 4.92L10.5 2.65L4.5 6.08L4.5 8.35L10.5 4.92L10.5 4.92ZM9.49 1.5L4.5 1.5L4.5 4.35L9.49 1.5L9.49 1.5ZM3.5 0L11.5 0C11.78 0 12 0.22 12 0.5L12 14.5C12 14.78 11.78 15 11.5 15L3.5 15C3.22 15 3 14.78 3 14.5L3 0.5C3 0.22 3.22 0 3.5 0Z"/>
+</svg>