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/maki/city.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg width="15" height="15" viewBox="0 0 15 15" xmlns="http://www.w3.org/2000/svg" id="city">
+  <path d="M12.6368 3.9994H10.9981V2.3608C10.998 2.16148 10.8364 1.99994 10.6371 2H10.3591C10.1598 2 9.9982 2.16158 9.9982 2.3609V3.9994H8.36C8.16068 3.9994 7.9991 4.16098 7.9991 4.3603V9.9984H4.3621C4.16168 9.9984 3.9992 10.1609 3.9992 10.3613V12.6358C3.99975 12.8358 4.16207 12.9977 4.3621 12.9977H12.6368C12.8361 12.9977 12.9977 12.8361 12.9977 12.6368V4.36C12.9977 4.16068 12.8361 3.9994 12.6368 3.9994ZM5.9989 11.9981H4.9989V10.9981H5.9989V11.9981ZM7.9989 11.9981H6.9989V10.9981H7.9989V11.9981ZM9.9989 11.9981H8.9989V10.9981H9.9989V11.9981ZM9.9989 9.9981H8.9989V8.9981H9.9989V9.9981ZM9.9989 7.9981H8.9989V6.9981H9.9989V7.9981ZM9.9989 5.9981H8.9989V4.9981H9.9989V5.9981ZM11.9989 11.9971H10.9989V10.9971H11.9989V11.9971ZM11.9989 9.9971H10.9989V8.9971H11.9989V9.9971ZM11.9989 7.9971H10.9989V6.9971H11.9989V7.9971ZM11.9989 5.9971H10.9989V4.9971H11.9989V5.9971ZM6.9987 2.3608C6.99864 2.16152 6.83708 2 6.6378 2H4.36C4.16068 2 3.9991 2.16158 3.9991 2.3609V4H2.36C2.16138 4.00049 2.00049 4.16138 2 4.36V12.6474C2 12.8407 2.1567 12.9974 2.35 12.9974H2.9994V8.9986H6.9987V2.3608ZM4 7.9981H3V6.9981H4V7.9981ZM4 5.9981H3V4.9981H4V5.9981ZM6 7.9981H5V6.9981H6V7.9981ZM6 5.9981H5V4.9981H6V5.9981ZM6 3.9981H5V3H6V4V3.9981Z"/>
+</svg>