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/rail_flag.svg

@@ -0,0 +1,4 @@
+<?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="M6 12L5.5 13L9.5 13L9 12L10.5 12L12 15L10.5 15L10 14L5 14L4.5 15L3 15L4.5 12L6 12ZM5.91 0.38C6.26 0.58 6.39 1.04 6.18 1.4L1.43 9.63C1.22 9.99 0.76 10.11 0.41 9.9C0.05 9.69 -0.08 9.24 0.13 8.88L4.88 0.65C5.09 0.29 5.55 0.17 5.91 0.38ZM3.5 7.04L6.5 1.84L9.59 2.53C9.69 2.55 9.78 2.6 9.85 2.68L11.88 4.9C11.95 4.97 12.04 5.02 12.14 5.05L14.56 5.58C14.83 5.64 15 5.91 14.94 6.18C14.93 6.23 14.91 6.28 14.89 6.32L12.41 10.61C12.3 10.8 12.08 10.89 11.87 10.85L9.14 10.24C9.04 10.22 8.95 10.17 8.88 10.09L6.85 7.87C6.78 7.8 6.69 7.75 6.59 7.72L3.5 7.04Z"/>
+</svg>