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/rocket_firework.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="M4.34 9L8.83 9L3.05 14.78L2.34 14.07L5.88 10.54L5.53 10.18L5.35 10.35C3.82 11.88 2.18 11.88 0.65 10.35L0.29 10L1 9.29L1.35 9.65C2.49 10.78 3.51 10.78 4.65 9.65L4.82 9.47L4.34 9L4.34 9ZM4.17 8L6.17 6L11.83 6L9.83 8L4.17 8ZM7.17 5L9.41 2.76L11.66 5L7.17 5L7.17 5ZM9 1L14 0.99L14 5.99L9 1Z"/>
+</svg>