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/village.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="village">
+  <path d="M6.176 1.176a.249.249 0 0 0-.352 0l-4.4 4.4A.25.25 0 0 0 1.6 6H3v6.751a.25.25 0 0 0 .249.249h3.5A.248.248 0 0 0 7 12.753v-7.43c0-.066.026-.13.073-.176L8.5 3.5 6.176 1.176ZM6 11H5v-1h1v1Zm0-2H5V8h1v1Zm0-3v1H5V6h1Z M12.75 3h-.5a.25.25 0 0 0-.25.25V5l-1.324-1.824a.249.249 0 0 0-.352 0L8.056 5.932A.246.246 0 0 0 8 6.088v6.66a.249.249 0 0 0 .246.252h1.5a.253.253 0 0 0 .254-.252V11h1v1.747a.253.253 0 0 0 .253.253h1.5a.25.25 0 0 0 .247-.249V3.25a.25.25 0 0 0-.25-.25ZM10 8H9V7h1v1Zm2 0h-1V7h1v1Zm-2 2H9V9h1v1Zm2 0h-1V9h1v1Z"/>
+</svg>