Add SPDX header template

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

.idea/copyright/Nextcloud___Android_Client.xml

@@ -0,0 +1,6 @@
+<component name="CopyrightManager">
+  <copyright>
+    <option name="notice" value="Nextcloud - Android Client&#10;&#10;SPDX-FileCopyrightText: &amp;#36;{today.year} Your Name &lt;your@email.com&gt;&#10;SPDX-License-Identifier: AGPL-3.0-or-later" />
+    <option name="myName" value="Nextcloud - Android Client" />
+  </copyright>
+</component>

.idea/copyright/profiles_settings.xml

@@ -0,0 +1,3 @@
+<component name="CopyrightManager">
+  <settings default="Nextcloud - Android Client" />
+</component>