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/shield.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="M7.5 3.18C6.47 4.05 5.3 4.5 4 4.5C3.58 4.5 3.13 4.42 2.62 4.26C3.06 8.14 4.68 10.78 7.5 12.32L7.5 3.18L7.5 3.18ZM1 2C1 2 3 3 4 3C5.33 3 6.5 2.33 7.5 1C8.5 2.33 9.67 3 11 3C12 3 14 2 14 2C14 8 11.83 12 7.5 14C3.17 12 1 8 1 2Z"/>
+</svg>