Add license information to files in matrix-base

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

roles/custom/matrix-base/tasks/setup_matrix_base.yml

@@ -1,3 +1,15 @@
+# SPDX-FileCopyrightText: 2017 - 2025 Slavi Pantaleev
+# SPDX-FileCopyrightText: 2018 - 2022 MDAD project contributors
+# SPDX-FileCopyrightText: 2019 Stuart Mumford
+# SPDX-FileCopyrightText: 2020 Béla Becker
+# SPDX-FileCopyrightText: 2020 Chris van Dijk
+# SPDX-FileCopyrightText: 2020 Horvath Gergely
+# SPDX-FileCopyrightText: 2022 Sebastian Gumprich
+# SPDX-FileCopyrightText: 2024 - 2025 Suguru Hirahara
+# SPDX-FileCopyrightText: 2024 László Várady
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
 ---
 
 - name: Ensure Matrix base paths exists