Add license information to files in group_vars

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

group_vars/jitsi_jvb_servers

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2023 Antonis Christofides
+#
+# SPDX-License-Identifier: AGPL-3.0-or-later
+
 jitsi_architecture: "{{ matrix_architecture }}"
 jitsi_hostname: "{{ matrix_server_fqn_jitsi }}"
 jitsi_uid: "{{ matrix_user_uid }}"