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/icons/maki/park-alt1.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg id="park-alt1" xmlns="http://www.w3.org/2000/svg" width="15" height="15" viewBox="0 0 15 15">
+  <path d="M9.428,10.429a.269.269,0,0,1-.074-.18A.25.25,0,0,1,9.6,10h1.447a.25.25,0,0,0,.25-.25.258.258,0,0,0-.079-.179L9.07,7.419a.3.3,0,0,1-.063-.17A.249.249,0,0,1,9.257,7H10.4a.251.251,0,0,0,.25-.251.247.247,0,0,0-.077-.178L8.432,4.434,8.418,4.42a.262.262,0,0,1-.066-.17A.25.25,0,0,1,8.6,4h.866a.25.25,0,0,0,.25-.25.246.246,0,0,0-.068-.164h.006L7.7,1.238a.253.253,0,0,0-.042-.044A.249.249,0,0,0,7.5,1.139h0a.249.249,0,0,0-.158.055.253.253,0,0,0-.042.044L5.352,3.586a.246.246,0,0,0-.068.164.25.25,0,0,0,.25.25H6.4a.241.241,0,0,1,.184.42l-.014.014L4.431,6.571a.247.247,0,0,0-.077.178A.251.251,0,0,0,4.6,7H5.745a.249.249,0,0,1,.25.249.3.3,0,0,1-.063.17L3.782,9.571A.258.258,0,0,0,3.7,9.75a.25.25,0,0,0,.25.25H5.4a.25.25,0,0,1,.248.249.269.269,0,0,1-.074.18l-2.14,2.132-.009.009a.248.248,0,0,0,0,.351A.256.256,0,0,0,3.605,13H7v1l1-.008V13h3.391a.263.263,0,0,0,.26-.254.248.248,0,0,0-.071-.177Z"/>
+</svg>