add coturn support for raspberry pi

roles/matrix-base/tasks/setup_matrix_base.yml

@@ -22,8 +22,9 @@
     group: "{{ matrix_user_username }}"
   with_items:
     - "{{ matrix_base_data_path }}"
-    - "{{ matrix_docker_src_files_path }}"
-    - "{{ matrix_docker_synapse_src_files_path }}"
+    - { src: "{{ matrix_docker_src_files_path }}", when: "{{ matrix_raspberry_pi }}" }
+    - { src: "{{ matrix_docker_synapse_src_files_path }}", when: "{{ matrix_raspberry_pi }}" }
+    - { src: "{{ matrix_docker_coturn_src_files_path }}", when: "{{ matrix_coturn_enabled }}"}
 
 # `docker_network` doesn't work as expected when the given network
 # is a substring of a network that already exists.