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/en/40c3/congress-lounge/index.md

@@ -0,0 +1,23 @@
+---
+title: '40C3 Congress Lounge'
+date: 2026-10-16T15:49:22+02:00
+summary: |
+    dj-spock explains the concept of the Lounge, how the booking works, and the audio and lighting technology. Which well-known and interesting people have already performed in the Congress Lounge?
+params:
+  geo:
+    lat: 53.562455
+    lon: 9.975361
+---
+
+dj-spock explains the concept of the Lounge, how the booking works, and the audio and lighting technology. Which well-known and interesting people have already performed in the Congress Lounge?
+
+What challenges does a dance event entail? Festival organizers and club operators talk about their experiences.
+
+## Details
+
+* Tour: Day 1 (27 December) **16:00** {{< calendar date="2026-12-27" time="16:00" duration="140" >}}
+* Duration: 2 hours
+* Language: German and English
+* Meeting time at Hackertours Desk: **as mentioned above**.
+* Accessibility: The lounge is fully accessible. It is possible that the dj and light consoles will have restrictions (stairs).
+* Location: Lounge at 40C3