Update docs for components related to authentication: add copyright headers

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

docs/configuring-playbook-ldap-auth.md

@@ -1,3 +1,12 @@
+<!--
+SPDX-FileCopyrightText: 2018 - 2022 Slavi Pantaleev
+SPDX-FileCopyrightText: 2019 - 2023 MDAD project contributors
+SPDX-FileCopyrightText: 2020 Marcel Partap
+SPDX-FileCopyrightText: 2024 Suguru Hirahara
+
+SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
 # Setting up the LDAP authentication password provider module (optional, advanced)
 
 The playbook can install and configure the [matrix-synapse-ldap3](https://github.com/matrix-org/matrix-synapse-ldap3) LDAP Auth password provider for you.

docs/configuring-playbook-rest-auth.md

@@ -1,3 +1,11 @@
+<!--
+SPDX-FileCopyrightText: 2018 - 2019 Slavi Pantaleev
+SPDX-FileCopyrightText: 2019 - 2020 Marcel Partap
+SPDX-FileCopyrightText: 2024 Suguru Hirahara
+
+SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
 # Setting up the REST authentication password provider module (optional, advanced)
 
 The playbook can install and configure [matrix-synapse-rest-auth](https://github.com/ma1uta/matrix-synapse-rest-password-provider) for you.

docs/configuring-playbook-shared-secret-auth.md

@@ -1,3 +1,11 @@
+<!--
+SPDX-FileCopyrightText: 2018 - 2020 Slavi Pantaleev
+SPDX-FileCopyrightText: 2020 MDAD project contributors
+SPDX-FileCopyrightText: 2024 Suguru Hirahara
+
+SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
 # Setting up the Shared Secret Auth password provider module (optional, advanced)
 
 The playbook can install and configure [matrix-synapse-shared-secret-auth](https://github.com/devture/matrix-synapse-shared-secret-auth) for you.