Discover Web App Manifest in HTML

... and return a hash of the JSON data.

spec/fixtures/mastodon-web-app-manifest.json

@@ -0,0 +1,20 @@
+{
+  "name": "kosmos.social",
+  "short_name": "kosmos.social",
+  "description": "A friendly place for tooting. Run by the Kosmos peeps.",
+  "icons": [
+    {
+      "src": "/android-chrome-192x192.png",
+      "sizes": "192x192",
+      "type": "image/png"
+    }
+  ],
+  "theme_color": "#282c37",
+  "background_color": "#191b22",
+  "display": "standalone",
+  "start_url": "/web/timelines/home",
+  "scope": "https://kosmos.social/",
+  "share_target": {
+    "url_template": "share?title={title}&text={text}&url={url}"
+  }
+}