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/blood-bank.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="blood-bank">
+  <path d="m11.2 6.1-3.7-5.1-3.7 5.1c-.5.7-.8 1.6-.8 2.5 0 2.4 2 4.4 4.5 4.4s4.5-2 4.5-4.4c0-.9-.3-1.8-.8-2.5zm-1.2 2.9h-2v2h-1v-2h-2v-1h2v-2h1v2h2z"/>
+</svg>