fix: add license information

Author: mykh-hailo

app/src/main/res/layout/sidebar.xml

@@ -1,6 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!--
   ~ Nextcloud - Android Client
+  ~
+  ~ SPDX-FileCopyrightText: 2021 Andy Scherzinger <info@andy-scherzinger>
+  ~ SPDX-FileCopyrightText: 2016 Nextcloud
+  ~ SPDX-License-Identifier: AGPL-3.0-or-later OR GPL-2.0-only
 -->
 <com.google.android.material.navigation.NavigationView
     xmlns:android="http://schemas.android.com/apk/res/android"

app/src/main/res/values-sw600dp/bool.xml

@@ -1,6 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!--
   ~ Nextcloud - Android Client
+  ~
+  ~ SPDX-FileCopyrightText: 2021-2024 Nextcloud GmbH and Nextcloud contributors
+  ~ SPDX-FileCopyrightText: 2021 Tobias Kaminsky <tobias@kaminsky.me>
+  ~ SPDX-License-Identifier: AGPL-3.0-or-later OR GPL-2.0-only
 -->
 <resources>
     <bool name="is_support_drawer">false</bool>

app/src/main/res/values-w600dp/bool.xml

@@ -1,6 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <!--
   ~ Nextcloud - Android Client
+  ~
+  ~ SPDX-FileCopyrightText: 2021-2024 Nextcloud GmbH and Nextcloud contributors
+  ~ SPDX-FileCopyrightText: 2021 Tobias Kaminsky <tobias@kaminsky.me>
+  ~ SPDX-License-Identifier: AGPL-3.0-or-later OR GPL-2.0-only
 -->
 <resources>
     <bool name="is_support_drawer">false</bool>