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/table_soccer.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 1A1 1 0 0 0 4 4A1 1 0 0 0 4 1ZM2 4.5H6V7L5 8L5.5 10L5 11A2 2 0 0 0 4.15 14.5H2.5V13L3 12V11L2.5 10L3 8L2 7ZM1.5 4.75H1A2 2 0 0 0 1 6.75H1.5ZM6.5 4.75H8.5V6.75H6.5ZM5.5 11.5A1 1 0 0 0 5.5 14.5A1 1 0 0 0 5.5 11.5ZM11 1A1 1 0 0 0 11 4A1 1 0 0 0 11 1ZM9 4.5H13V7L12 8L12.5 10L12 11V12L12.5 13V14.5H9.5V13L10 12V11L9.5 10L10 8L9 7ZM13.5 4.75H14A2 2 0 0 1 14 6.75H13.5Z"/>
+</svg>