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/play_structure.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 10L6 10.01L6 14L5 14L5 11.13L2.75 13.66C2.38 14.08 1.75 14.11 1.34 13.75C0.92 13.38 0.89 12.75 1.25 12.34L5 8.12L5 4L4 4L4 3L7.5 1L11 3L11 4L10 4L10 8L12.5 12L13 12C13.55 12 14 12.45 14 13L14 13C14 13.55 13.55 14 13 14C13 14 13 14 13 14L11.5 14L10 11.6L10 14L9 14L9 10L6 10ZM6.59 7.69C6.6 7.7 6.6 7.7 6.61 7.71C6.86 7.89 7.17 8 7.5 8C8.33 8 9 7.33 9 6.5C9 5.67 8.33 5 7.5 5C6.67 5 6 5.67 6 6.5C6 6.99 6.23 7.42 6.59 7.69L6.59 7.69Z"/>
+</svg>