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/suitcase.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="suitcase">
+  <path d="M4.5 4V2C4.5 1.44772 4.94772 1 5.5 1H9.5C10.0523 1 10.5 1.44772 10.5 2V4H12C12.5523 4 13 4.44772 13 5V11C13 11.5523 12.5523 12 12 12H3C2.44771 12 2 11.5523 2 11V5C2 4.44772 2.44772 4 3 4H4.5ZM5.5 2V4H9.5V2H5.5Z"/>
+</svg>