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/sailboat.svg

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 48 47.99975" x="0px" y="0px">
+  <path d="M3.98 36H16.02A0.98 0.98 0 0 0 17 35.02V17a0.98 0.98 0 0 0 -1.8 -0.54L3.17 34.48A0.98 0.98 0 0 0 3.98 36Z"/>
+  <path d="M20 36H43.99a1 1 0 0 0 1.01 -1.02C44.58 16.6 32.84 0.76 20.03 0a0.99 0.99 0 0 0 -1.03 1V35A1 1 0 0 0 20 36Z"/>
+  <path d="M46 39H2a2 2 0 0 0 -2 2a7 7 0 0 0 7 7H41a7 7 0 0 0 7 -7A2 2 0 0 0 46 39Z"/>
+</svg>