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/temaki/turnstile.svg

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg viewBox="0 0 15 15" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
+  <path d="M3.5 1C4.33 1 5 1.67 5 2.5L5 14L2 14L2 2.5C2 1.67 2.67 1 3.5 1Z"/>
+  <path d="M5 4.15C4.64 4.15 4.35 3.86 4.35 3.5C4.35 3.14 4.64 2.85 5 2.85L12.5 2.85C12.86 2.85 13.15 3.14 13.15 3.5C13.15 3.86 12.86 4.15 12.5 4.15L5 4.15Z"/>
+  <path d="M8.12 9.81C8.23 10.15 8.03 10.52 7.69 10.62C7.35 10.73 6.98 10.53 6.88 10.19L4.97 3.98C4.86 3.64 5.05 3.27 5.4 3.17C5.74 3.06 6.1 3.25 6.21 3.6L8.12 9.81Z"/>
+  <path d="M11.38 6.97C11.67 7.19 11.74 7.59 11.53 7.88C11.31 8.17 10.91 8.24 10.62 8.03L5.36 4.2C5.07 3.99 5.01 3.58 5.22 3.29C5.43 3 5.84 2.94 6.13 3.15L11.38 6.97Z"/>
+</svg>