Add three-up evidence boards for El Capitan and Joke Shop

docs/screens/boards/elcapitan-night-board.json

@@ -0,0 +1,7 @@
+{
+  "board": "elcapitan-night-board.jpg",
+  "caption": "El Capitan block, night: CC BY-SA photo (redistribution only) | photo-anchored concept | current capture",
+  "photo": "docs/screens/refs/hollywood/hollywood-boulevard-night-context-ccbysa.jpg",
+  "concept": "docs/screens/concepts/hollywood_boulevard/el_capitan_facade_night.png",
+  "capture": "docs/screenshots/05-late-night-avenue.png"
+}