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/paint.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg height="15" viewBox="0 0 15 15" width="15" xmlns="http://www.w3.org/2000/svg" id="paint">
+  <path d="m13.5 3.5h-1v-.9973c0-.2777-.2251-.5027-.5027-.5027h-10.4946c-.2776 0-.5027.225-.5027.5027v2.9946c0 .2776.2251.5027.5027.5027h10.4946c.2776 0 .5027-.2251.5027-.5027v-.9973h.5v3.1021l-6.1123 1.4106c-.2271.0527-.3877.2549-.3877.4873v1.5074c-.2783.02-.5.246-.5.5295v2.9261c0 .2966.2404.537.5369.537h.9261c.2966 0 .537-.2404.537-.5369v-2.9261c0-.2834-.2217-.5095-.5-.5295v-1.11l6.1123-1.4102c.2266-.0522.3877-.2544.3877-.4873v-4c0-.2764-.2236-.5-.5-.5z"/>
+</svg>