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/campfire.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="M12 13.83L12 11.89L3 9.08L3 11.02L12 13.83ZM5.08 9.08C4.77 8.76 2.71 6.53 4.78 4.61C6.52 3 6.77 1.65 6.18 1C6.18 1 10.59 2.69 8 6.62C7.55 7.28 6.45 8.07 7.03 9.69L5.08 9.08L5.08 9.08ZM7.78 9.61C7.69 9.29 7.26 8.57 8.55 7.14C9.24 6.38 9.5 5.25 9.56 4.83C9.56 4.83 11.84 6.05 9.57 9.05L7.78 9.61L7.78 9.61ZM8.26 10.07L12 8.91L12 10.85L11.37 11.04L8.26 10.07ZM6.74 12.84L3 14L3 12.06L3.64 11.87L6.74 12.84Z"/>
+</svg>