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/brands/orcid.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512"><!--! 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="M294.7 188.2l-45.9 0 0 153.8 47.5 0c67.6 0 83.1-51.3 83.1-76.9 0-41.6-26.5-76.9-84.7-76.9zM256 8a248 248 0 1 0 0 496 248 248 0 1 0 0-496zM175.2 368.8l-29.8 0 0-207.5 29.8 0 0 207.5zM160.3 98.5a19.6 19.6 0 1 1 0 39.2 19.6 19.6 0 1 1 0-39.2zM300 369l-81 0 0-207.7 80.6 0c76.7 0 110.4 54.8 110.4 103.9 0 53.3-41.7 103.9-110 103.9z"/></svg>