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/campsite.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="15" height="15" viewBox="0 0 15 15" xmlns="http://www.w3.org/2000/svg" id="campsite">
+  <path d="M14 10V11C14 11.5523 13.5523 12 13 12H2C1.44772 12 1 11.5523 1 11V10C1 9.44772 1.44772 9.00001 2 9.00001H2.25L7.03206 1.25762C7.24699 0.90965 7.75302 0.909651 7.96794 1.25762L12.75 9.00001H13C13.5523 9.00001 14 9.44772 14 10ZM10.5 9.00001L7.5 4.00001L4.5 9.00001H10.5Z"/>
+</svg>