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/mobile-phone.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg id="mobile-phone" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M10,2h0V1.5a.5.5,0,0,0-1,0V2H5A1,1,0,0,0,4,3V13a1,1,0,0,0,1,1h5a1,1,0,0,0,1-1V3A1,1,0,0,0,10,2ZM6,13H5V12H6Zm0-2H5V10H6ZM6,9H5V8H6Zm2,4H7V12H8Zm0-2H7V10H8ZM8,9H7V8H8Zm2,4H9V12h1Zm0-2H9V10h1Zm0-2H9V8h1Zm0-2.5a.5.5,0,0,1-.5.5h-4A.5.5,0,0,1,5,6.5v-3A.5.5,0,0,1,5.5,3h4a.5.5,0,0,1,.5.5Z"/>
+</svg>