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/vacuum_station.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 6L4 14L0 14L0 3C0 1.9 0.9 1 2 1C3.1 1 4 1.9 4 3L4 4L5.26 4C5.87 2.25 7.54 1 9.5 1C11.99 1 14 3.01 14 5.5L14 9.5L12 9.5L12 5.5C12 4.12 10.88 3 9.5 3C8.68 3 7.96 3.39 7.5 4L8 4C9.66 4 11 5.34 11 7L11 11C11 12.66 9.66 14 8 14C6.34 14 5 12.66 5 11L5 6L4 6ZM12 10L14 10L14 12L15 13L15 14L11 14L11 13L12 12L12 10ZM7 11C7 11.55 7.45 12 8 12C8.55 12 9 11.55 9 11L9 7C9 6.45 8.55 6 8 6L7 6L7 11Z"/>
+</svg>