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/anvil.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="M11 9.5L13 11L13 12L11 12C10.33 11.33 9.5 11 8.5 11C7.5 11 6.67 11.33 6 12L4 12L4 11L6 9.5L11 9.5ZM15 4L15 5C12.86 5 11.11 6.68 11 8.8L11 9L6 9C6 8.36 5.75 7.75 5.29 7.29L5 7L5 4L15 4ZM0 4.5L4.5 4.5L4.5 7C2.83 7 1.33 6.17 0 4.5Z"/>
+</svg>