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/wrench.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="M509.4 98.6c7.6-7.6 20.3-5.7 24.1 4.3 6.8 17.7 10.5 37 10.5 57.1 0 88.4-71.6 160-160 160-17.5 0-34.4-2.8-50.2-8L146.9 498.9c-28.1 28.1-73.7 28.1-101.8 0s-28.1-73.7 0-101.8L232 210.2c-5.2-15.8-8-32.6-8-50.2 0-88.4 71.6-160 160-160 20.1 0 39.4 3.7 57.1 10.5 10 3.8 11.8 16.5 4.3 24.1l-88.7 88.7c-3 3-4.7 7.1-4.7 11.3l0 41.4c0 8.8 7.2 16 16 16l41.4 0c4.2 0 8.3-1.7 11.3-4.7l88.7-88.7z"/></svg>