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/user-ninja.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512"><!--! 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="M352 128c0 70.7-57.3 128-128 128-57.2 0-105.6-37.5-122-89.3-1.1 1.3-2.2 2.6-3.5 3.8-15.8 15.8-38.8 20.7-53.6 22.1-8.1 .8-14.6-5.7-13.8-13.8 1.4-14.7 6.3-37.8 22.1-53.6 5.8-5.8 12.6-10.1 19.6-13.4-7-3.2-13.8-7.6-19.6-13.4-15.8-15.8-20.7-38.8-22.1-53.6-.8-8.1 5.7-14.6 13.8-13.8 14.7 1.4 37.8 6.3 53.6 22.1 4.8 4.8 8.7 10.4 11.7 16.1 21.3-41.2 64.3-69.4 113.8-69.4 70.7 0 128 57.3 128 128zM144 112c0 8.8 7.2 16 16 16l128 0c8.8 0 16-7.2 16-16s-7.2-16-16-16L160 96c-8.8 0-16 7.2-16 16zm-1.4 211l67 50.2c8.5 6.4 20.3 6.4 28.8 0l67-50.2c6.5-4.9 15.2-6.2 22.6-2.8 61.4 28.2 104.1 90.2 104.1 162.1 0 16.4-13.3 29.7-29.7 29.7L45.7 512c-16.4 0-29.7-13.3-29.7-29.7 0-72 42.7-134 104.1-162.1 7.4-3.4 16.1-2.1 22.6 2.8z"/></svg>