Put static assets in a separate directory so they can be delivered directly by nginx

templates/manifest.webmanifest

@@ -0,0 +1,29 @@
+{
+    "dir": "ltr",
+    "lang": "English",
+    "name": "Spothole",
+    "short_name": "Spothole",
+    "scope": "/",
+    "display": "standalone",
+    "start_url": "{{ baseurl }}",
+    "background_color": "white",
+    "theme_color": "white",
+    "description": "An Amateur Radio spotting tool bringing together DX clusters and outdoor programmes, providing a universal JSON API and web interface.",
+    "related_applications": [],
+    "prefer_related_applications": false,
+    "icons": [
+    {
+      "src": "/static/img/icon-192-pwa.png",
+      "type": "image/png",
+      "sizes": "192x192",
+      "purpose": "maskable"
+    },
+    {
+      "src": "/static/img/icon-512-pwa.png",
+      "type": "image/png",
+      "sizes": "512x512",
+      "purpose": "maskable"
+    }
+  ],
+  "url": "{{ baseurl }}"
+}