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/vertical_rotisserie.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="M11.23 11.74L11.22 11.77C11.09 12.48 10.47 13 9.75 13L5.25 13C4.53 13 3.91 12.48 3.78 11.77L3.6 10.8L6 10L3.29 9.1L3.06 7.81L5.5 7L2.74 6.08L2.51 4.83L5 4L2.35 3.12C2.49 2.57 2.94 2.13 3.53 2.02C3.62 2.01 3.71 2 3.8 2L11.2 2C12.03 2 12.7 2.67 12.7 3.5C12.7 3.59 12.69 3.68 12.68 3.77L12.61 4.13L10 5L12.31 5.77L12.06 7.15L9.5 8L11.77 8.76L11.52 10.16L9 11L11.23 11.74L11.23 11.74ZM7 0L8 0L8 1.5L7 1.5L7 0ZM7 13.5L8 13.5L8 15L7 15L7 13.5Z"/>
+</svg>