Add documentation for android deep link handling

Signed-off-by: alperozturk <alper_ozturk@proton.me>

admin_manual/configuration_server/android_deep_link_handling.rst

@@ -0,0 +1,47 @@
+=================
+Deep Link Handling
+=================
+
+Deep linking in Android allows your application to be launched directly from a URL, 
+making it easier for users to navigate to specific content within your app. 
+Starting from Android 12, handling deep links requires additional configuration 
+using an assetlinks.json file to ensure the app and the host domain are properly 
+associated.
+
+Deep Linking in Android 11 and Below
+    For Android 11 and below, deep linking is straightforward and does not require additional 
+    configuration beyond the usual manifest settings.
+
+
+Deep Linking in Android 12 and Above
+    For Android 12 and above, an additional configuration step is required to verify the 
+    relationship between your app and the host domain using the assetlinks.json file.
+
+    Creating assetlinks.json:
+        Create a file named assetlinks.json and host it in the .well-known directory of 
+        your website (e.g., https://www.cloud.example.com/.well-known/assetlinks.json).
+
+        Example assetlinks.json::
+        [
+        {
+            "relation": ["delegate_permission/common.handle_all_urls"],
+            "target": {
+            "namespace": "android_app",
+            "package_name": "com.cloud.example.nextcloud",
+            "sha256_cert_fingerprints": [
+                "APP_SHA256_FINGERPRINT"
+            ]
+            }
+        }
+        ]
+
+        Replace APP_SHA256_FINGERPRINT with the SHA-256 fingerprint of your app’s 
+        signing certificate.
+
+
+Nextcloud Configuration Limitation
+    Due to the additional requirement of hosting an assetlinks.json file 
+    for Android 12 and above, Nextcloud cannot configure the Android client 
+    for all different hosts. This is because each host needs its own assetlinks.json 
+    file to establish a verified relationship with the app, and Nextcloud cannot manage 
+    this file for every possible host domain.