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/religious-muslim.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="religious-muslim">
+  <path d="M12.0962 12.0962C9.55779 14.6346 5.44221 14.6346 2.90381 12.0962C0.365398 9.55779 0.365398 5.44221 2.90381 2.90381C5.44221 0.365398 9.55779 0.365398 12.0962 2.90381C12.2675 3.07512 12.4273 3.25362 12.5754 3.43832C10.5566 1.86336 7.63341 2.00437 5.77643 3.86135C3.76685 5.87092 3.76685 9.12908 5.77643 11.1387C7.63341 12.9956 10.5566 13.1366 12.5754 11.5617C12.4273 11.7464 12.2675 11.9249 12.0962 12.0962Z M10.1 6.5H8L9.7 8L9 10.5L11 9L13 10.5L12.3 8L14 6.5H11.9L11 4.5L10.1 6.5Z"/>
+</svg>