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/road-lock.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="M256 32l-76.3 0c-29.4 0-55.1 20.1-62.1 48.6L33.4 420.5C25.9 450.7 48.8 480 80 480l175.9 0 0-64c0-17.7 14.3-32 32-32 6.1 0 11.8 1.7 16.7 4.7 2.8-23.9 14.3-45.1 31.4-60.3l0-24.4c0-70.7 57.3-128 128-128 6.2 0 12.4 .4 18.4 1.3L458.5 80.6C451.4 52.1 425.8 32 396.3 32l-76.4 0 0 64c0 17.7-14.3 32-32 32s-32-14.3-32-32l0-64zm64 192l0 64c0 17.7-14.3 32-32 32s-32-14.3-32-32l0-64c0-17.7 14.3-32 32-32s32 14.3 32 32zm176 80.1l0 47.9-64 0 0-47.9c0-17.7 14.3-32 32-32s32 14.3 32 32zM352 400l0 96c0 26.5 21.5 48 48 48l128 0c26.5 0 48-21.5 48-48l0-96c0-20.9-13.4-38.7-32-45.3l0-50.6c0-44.2-35.8-80-80-80s-80 35.8-80 80l0 50.6c-18.6 6.6-32 24.4-32 45.3z"/></svg>