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

docs/screens/boards/jokeshop-day-board.json

@@ -0,0 +1,7 @@
+{
+  "board": "jokeshop-day-board.jpg",
+  "caption": "Joke Shop, day: licensed photo | generated concept | current capture",
+  "photo": "docs/screens/refs/joke-shop/comedy-store-frontage-palms-day-pd-2006-12-29.jpg",
+  "concept": "docs/screens/concepts/joke_shop/joke_shop_entrance_day.png",
+  "capture": "docs/screenshots/12-joke-shop.png"
+}