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/democrat.svg

@@ -0,0 +1 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 640 512"><!--! 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="M64 32c0-8.9 3.8-20.9 6.2-27.3 1-2.8 3.8-4.7 6.8-4.7 1.9 0 3.8 .7 5.2 2.1L128 45.7 173.8 2.1c1.4-1.3 3.2-2.1 5.2-2.1 3 0 5.8 1.8 6.8 4.7 2.4 6.5 6.2 18.4 6.2 27.3 0 26.5-21.9 42-29.5 46.6l76.2 72.6c6 5.7 13.9 8.8 22.1 8.8l219.2 0 32 0c40.3 0 78.2 19 102.4 51.2l19.2 25.6c10.6 14.1 7.7 34.2-6.4 44.8s-34.2 7.7-44.8-6.4l-19.2-25.6c-5.3-7-11.8-12.8-19.2-17l0 87.4-352 0-40.4-94.3c-3.9-9.2-15.3-12.6-23.6-7l-42.1 28c-9.1 6.1-19.7 9.3-30.7 9.3l-2 0C23.9 256 0 232.1 0 202.7 0 190.6 4.1 178.9 11.7 169.4L87.6 74.6C78.1 67.4 64 53.2 64 32zM544 352l0 128c0 17.7-14.3 32-32 32l-32 0c-17.7 0-32-14.3-32-32l0-64-160 0 0 64c0 17.7-14.3 32-32 32l-32 0c-17.7 0-32-14.3-32-32l0-128 352 0zM256 280a24 24 0 1 0 0-48 24 24 0 1 0 0 48zm248-24a24 24 0 1 0 -48 0 24 24 0 1 0 48 0zM368 280a24 24 0 1 0 0-48 24 24 0 1 0 0 48z"/></svg>