chore: initialize extension with manifest

manifest.json

@@ -0,0 +1,18 @@
+{
+  "manifest_version": 3,
+  "name": "Buienradar Pay/OK Clicker",
+  "version": "1.0.0",
+  "description": "Automatisch 'gratis met persoonlijke advertenties' selecteren op Buienradar",
+  "content_scripts": [
+    {
+      "matches": ["*://*.buienradar.nl/*"],
+      "js": ["content.js"],
+      "run_at": "document_end"
+    }
+  ],
+  "icons": {
+    "16": "icon16.png",
+    "48": "icon48.png",
+    "128": "icon128.png"
+  }
+}