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/file-circle-question.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="M96 0C60.7 0 32 28.7 32 64l0 384c0 35.3 28.7 64 64 64l180 0c-22.7-31.5-36-70.2-36-112 0-100.6 77.4-183.2 176-191.3l0-38.1c0-17-6.7-33.3-18.7-45.3L290.7 18.7C278.7 6.7 262.5 0 245.5 0L96 0zM357.5 176L264 176c-13.3 0-24-10.7-24-24L240 58.5 357.5 176zM432 544a144 144 0 1 0 0-288 144 144 0 1 0 0 288zm0-100a20 20 0 1 1 0 40 20 20 0 1 1 0-40zm0-100c-11.6 0-21.3 8.2-23.5 19.2-1.8 8.7-10.2 14.3-18.9 12.5s-14.3-10.2-12.5-18.9c5.2-25.6 27.8-44.8 54.9-44.8 30.9 0 56 25.1 56 56 0 19.8-11.7 37.8-29.8 45.9l-10.4 4.6c-1.2 7.7-7.8 13.5-15.8 13.5-8.8 0-16-7.2-16-16 0-11.2 6.6-21.3 16.8-25.9l12.4-5.5c6.6-2.9 10.8-9.4 10.8-16.6 0-13.3-10.7-24-24-24z"/></svg>