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/gate.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="15" height="15" viewBox="0 0 15 15" xmlns="http://www.w3.org/2000/svg" id="gate">
+  <path d="M1 2.75A.75.75 0 0 1 1.75 2h1.114c.09 0 .18.016.263.048l3.386 1.27A.75.75 0 0 1 7 4.02v5.96a.75.75 0 0 1-.487.702L3 12v.25a.75.75 0 0 1-.75.75h-.5a.75.75 0 0 1-.75-.75v-9.5Zm3 5.736v-4.87a.25.25 0 0 0-.162-.234l-.5-.187A.25.25 0 0 0 3 3.429v5.224c0 .17.167.291.33.237l.5-.166A.25.25 0 0 0 4 8.486ZM5 4.18v3.807a.25.25 0 0 0 .33.238l.5-.167A.25.25 0 0 0 6 7.82V4.366a.25.25 0 0 0-.162-.234l-.5-.187A.25.25 0 0 0 5 4.179Zm9-1.43a.75.75 0 0 0-.75-.75h-1.114a.75.75 0 0 0-.263.048l-3.386 1.27A.75.75 0 0 0 8 4.02v5.96a.75.75 0 0 0 .487.702L12 12v.25c0 .414.336.75.75.75h.5a.75.75 0 0 0 .75-.75v-9.5Zm-2.83 5.974a.25.25 0 0 1-.17-.238v-4.87a.25.25 0 0 1 .162-.234l.5-.187a.25.25 0 0 1 .338.234v5.224a.25.25 0 0 1-.33.237l-.5-.166ZM10 4.179v3.807a.25.25 0 0 1-.33.238l-.5-.167A.25.25 0 0 1 9 7.82V4.366a.25.25 0 0 1 .162-.234l.5-.187a.25.25 0 0 1 .338.234Z"/>
+</svg>