Remove unused PWA / manifest code

Had discussed this with Abhinav, there were some issues around marking our app
as a PWA, tied to worker lifetime, so the PWA functionality had been disabled,
and these files are not currently not supposed to be used.

apps/photos/public/manifest.json

@@ -1,66 +0,0 @@
-{
-    "short_name": "Ente Photos",
-    "name": "Ente Photos | Safe home for your Photos",
-    "icons": [
-        {
-            "src": "/images/ente/192.png",
-            "type": "image/png",
-            "sizes": "192x192"
-        },
-        {
-            "src": "/images/ente/256.png",
-            "type": "image/png",
-            "sizes": "256x256"
-        },
-        {
-            "src": "/images/ente/512.png",
-            "type": "image/png",
-            "sizes": "512x512"
-        }
-    ],
-    "start_url": "/",
-    "background_color": "#191919",
-    "display": "standalone",
-    "scope": "/",
-    "theme_color": "#111",
-    "description": "ente provides a simple way to back up your memories.",
-    "prefer_related_applications": true,
-    "related_applications": [
-        {
-            "platform": "play",
-            "url": "https://play.google.com/store/apps/details?id=io.ente.photos",
-            "id": "io.ente.photos"
-        },
-        {
-            "platform": "itunes",
-            "url": "https://apps.apple.com/in/app/ente-photos/id1542026904"
-        }
-    ],
-    "screenshots": [
-        {
-            "src": "/pwa/slide-1.jpg",
-            "type": "image/jpeg",
-            "sizes": "417x760"
-        },
-        {
-            "src": "/pwa/slide-2.jpg",
-            "type": "image/jpeg",
-            "sizes": "378x690"
-        },
-        {
-            "src": "/pwa/slide-3.jpg",
-            "type": "image/jpeg",
-            "sizes": "378x690"
-        },
-        {
-            "src": "/pwa/slide-4.jpg",
-            "type": "image/jpeg",
-            "sizes": "378x690"
-        },
-        {
-            "src": "/pwa/slide-5.jpg",
-            "type": "image/jpeg",
-            "sizes": "378x690"
-        }
-    ]
-}