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.

content/de/40c3/_index.md

@@ -0,0 +1,23 @@
+---
+title: 40C3 Touren
+weight: 10
+layout: list-bytitle
+menus:
+  main:
+    name: Touren
+params:
+  showPostDate: false
+cascade:
+  params:
+    showPostDate: false
+---
+
+Diese Touren bieten wir zum 40C3 an:
+
+{{< schedule >}}
+
+Wir haben keine Touren an Tag 4 (30.12.).
+
+{{< tour-map >}}
+
+# Alle Touren in der Übersicht