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/car.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" id="car" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M13.84,6.852,12.6,5.7,11.5,3.5a1.05,1.05,0,0,0-.9-.5H4.4a1.05,1.05,0,0,0-.9.5L2.4,5.7,1.16,6.852A.5.5,0,0,0,1,7.219V11.5a.5.5,0,0,0,.5.5h2c.2,0,.5-.2.5-.4V11h7v.5c0,.2.2.5.4.5h2.1a.5.5,0,0,0,.5-.5V7.219A.5.5,0,0,0,13.84,6.852ZM4.5,4h6l1,2h-8ZM5,8.6c0,.2-.3.4-.5.4H2.4C2.2,9,2,8.7,2,8.5V7.4c.1-.3.3-.5.6-.4l2,.4c.2,0,.4.3.4.5Zm8-.1c0,.2-.2.5-.4.5H10.5c-.2,0-.5-.2-.5-.4V7.9c0-.2.2-.5.4-.5l2-.4c.3-.1.5.1.6.4Z"/>
+</svg>