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/rope_fence.svg

@@ -0,0 +1,6 @@
+<?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="M2 4C2.55 4 3 4.45 3 5L3 11L1 11L1 5C1 4.45 1.45 4 2 4Z"/>
+  <path d="M13 4C13.55 4 14 4.45 14 5L14 11L12 11L12 5C12 4.45 12.45 4 13 4Z"/>
+  <path d="M0.65 6.02C0.37 5.83 0.29 5.44 0.48 5.15C0.67 4.87 1.06 4.79 1.35 4.98C3.24 6.25 5.29 6.88 7.5 6.88C9.71 6.88 11.76 6.25 13.65 4.98C13.94 4.79 14.33 4.87 14.52 5.15C14.71 5.44 14.63 5.83 14.35 6.02C12.24 7.42 9.96 8.13 7.5 8.13C5.04 8.13 2.76 7.42 0.65 6.02Z"/>
+</svg>