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/bowling-alley.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="bowling-alley">
+  <path d="M10.922 3.166c0 1.006-.335 1.857-.693 2.77-.414 1.052-.86 2.185-.86 3.73 0 2.166.687 4.333 1.409 4.333h1.444c.723 0 1.409-2.166 1.409-4.333 0-1.545-.446-2.678-.86-3.73-.358-.912-.693-1.764-.693-2.77 0-.722.144-.723.144-1.445A.743.743 0 0 0 11.5.999a.743.743 0 0 0-.722.722c0 .723.144.723.144 1.445Zm-2.552 6.5c0-1.234.254-2.236.55-3.091a4.5 4.5 0 1 0-.17 6.038c-.237-.865-.38-1.91-.38-2.947ZM5.24 7.12a.62.62 0 1 1-1.24 0 .62.62 0 0 1 1.24 0Zm-1 2a.62.62 0 1 1-1.24 0 .62.62 0 0 1 1.24 0Zm2 0a.62.62 0 1 1-1.24 0 .62.62 0 0 1 1.24 0Z"/>
+</svg>