Release v3 with high-res splash screen. More details in web, app manifest

- Add 512, 192 Khoj maskable icons to web app manifest for android rendering
- Add id, categories etc suggested by pwabuilder
- Use higher quality icon images for splash screen than what
  bubblewrap creates by default

src/interface/web/public/khoj.webmanifest

@@ -1,12 +1,18 @@
 {
-    "name": "Khoj",
+    "id": "dev.khoj.app",
+    "name": "Khoj AI",
     "short_name": "Khoj",
     "display": "standalone",
     "start_url": "/",
     "scope": "/",
     "description": "The open, personal AI for your digital brain. You can ask Khoj to draft a message, paint your imagination, find information on the internet and even answer questions from your documents.",
+    "categories": ["productivity", "utilities", "personalization", "education"],
     "theme_color": "#ffffff",
     "background_color": "#ffffff",
+    "orientation": "any",
+    "launch_handler": {
+        "client_mode": ["navigate-existing", "auto"]
+    },
     "icons": [
         {
             "src": "/static/assets/icons/khoj_lantern_128x128.png",
@@ -17,6 +23,30 @@
             "src": "/static/assets/icons/khoj_lantern_256x256.png",
             "sizes": "256x256",
             "type": "image/png"
+        },
+        {
+            "src": "/static/assets/icons/khoj_lantern_192x192.png",
+            "sizes": "192x192",
+            "type": "image/png",
+            "purpose": "any"
+        },
+        {
+            "src": "/static/assets/icons/khoj_lantern_192x192.png",
+            "sizes": "192x192",
+            "type": "image/png",
+            "purpose": "maskable"
+        },
+        {
+            "src": "/static/assets/icons/khoj_lantern_512x512.png",
+            "sizes": "512x512",
+            "type": "image/png",
+            "purpose": "any"
+        },
+        {
+            "src": "/static/assets/icons/khoj_lantern_512x512.png",
+            "sizes": "512x512",
+            "type": "image/png",
+            "purpose": "maskable"
         }
     ],
     "screenshots": [