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/school.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="school">
+  <path d="M5.542 3.647 3.106 3l.443-1.63a.505.505 0 0 1 .618-.352l1.46.392a.5.5 0 0 1 .355.613l-.44 1.624Zm-4.52 7.356a.496.496 0 0 1-.005-.276l1.819-6.726 2.435.647-1.819 6.726a.499.499 0 0 1-.143.237l-1.457 1.347a.152.152 0 0 1-.247-.066l-.583-1.889ZM10 5c-2.25 0-3-.75-3-3 2.25 0 3 .75 3 3Zm-1.4 7.984c-1.37.21-3.126-1.706-3.52-3.8L5.969 5.9c.399-.35.903-.533 1.419-.533a2.71 2.71 0 0 1 1.564.489.964.964 0 0 0 1.089-.01 2.438 2.438 0 0 1 1.46-.479c.77 0 1.643.489 2.05 1.201 1.536 2.696-1.194 6.709-3.144 6.417a.867.867 0 0 1-.255-.093 1.427 1.427 0 0 0-1.302 0 .866.866 0 0 1-.25.092Z"/>
+</svg>