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/fontawesome/solid/crown.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 576 512"><!--! Font Awesome Free 7.3.1 by @fontawesome - https://fontawesome.com License - https://fontawesome.com/license/free (Icons: CC BY 4.0, Fonts: SIL OFL 1.1, Code: MIT License) Copyright 2026 Fonticons, Inc. --><path fill="currentColor" d="M313 87.2c9.2-7.3 15-18.6 15-31.2 0-22.1-17.9-40-40-40s-40 17.9-40 40c0 12.6 5.9 23.9 15 31.2L194.6 194.8c-10 15.7-31.3 19.6-46.2 8.4L88.9 158.7c4.5-6.4 7.1-14.3 7.1-22.7 0-22.1-17.9-40-40-40s-40 17.9-40 40c0 21.8 17.5 39.6 39.2 40L87.8 393.5c4.7 31.3 31.6 54.5 63.3 54.5l273.8 0c31.7 0 58.6-23.2 63.3-54.5L520.8 176c21.7-.4 39.2-18.2 39.2-40 0-22.1-17.9-40-40-40s-40 17.9-40 40c0 8.4 2.6 16.3 7.1 22.7l-59.4 44.6c-14.9 11.2-36.2 7.3-46.2-8.4L313 87.2z"/></svg>