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/highway-rest-area.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15" id="highway-rest-area">
+  <path d="M13.5,13h-3V9h3a.5.5,0,0,0,.4092-.7871L11.66,5h.84a.5.5,0,0,0,.3838-.82l-2.5-3a.5155.5155,0,0,0-.7676,0l-2.5,3A.5.5,0,0,0,7.5,5h.84L6.0908,8.2129A.5.5,0,0,0,6.5,9h3v4H4V11H5.5a.5.5,0,0,0,0-1h-4a.5.5,0,0,0,0,1H3v2H1.5a.5.5,0,0,0,0,1h12a.5.5,0,0,0,0-1Z"/>
+</svg>