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/karaoke.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15" id="karaoke">
+  <path d="M12.1,2.952A2.988,2.988,0,0,0,6.99,4.917l3.142,3.142A2.988,2.988,0,0,0,12.1,2.952Zm-7.428,5.3L2.55,10.377a1,1,0,0,0,0,1.414l.707.707a1,1,0,0,0,1.414,0l2.121-2.121L8.914,8.255,6.793,6.134Zm.741,2.087-.707-.707L6.793,7.548l.707.707Z"/>
+</svg>