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/fire-station.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="fire-station">
+  <path d="M7.5 14C11.0899 14 14 11 14 7.50003C14 4.5 11.5 2 11.5 2L10.5 5.5L7.5 1L4.5 5.5L3.5 2C3.5 2 1 4.5 1 7.50003C1 11 3.91015 14 7.5 14ZM7.5 12.5C6.11929 12.5 5 11.3807 5 10C5 8.61929 7.5 5.5 7.5 5.5C7.5 5.5 10 8.61929 10 10C10 11.3807 8.88071 12.5 7.5 12.5Z"/>
+</svg>