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/music.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="music">
+  <path d="m12.5 0c-.0804.0008-.1594.0213999-.23.0599999l-8.77 2.4400001c-.2761 0-.5.2239-.5.5v6.28c-.3029-.1798-.6478-.2763-1-.28-1.1046 0-2 .8954-2 2s.8954 2 2 2 2-.8954 2-2v-4.64l8-2.22v3.64c-.3029-.1798-.6478-.2763-1-.28-1.1046 0-2 .8954-2 2s.8954 2 2 2 2-.8954 2-2v-9c0-.2761-.2239-.5-.5-.5zm-.5 3.14-8 2.22v-2l8-2.22z"/>
+</svg>