Add matrix_synapse_email_app_name variable

roles/custom/matrix-synapse/defaults/main.yml

@@ -706,6 +706,7 @@ matrix_synapse_email_smtp_user: ""
 matrix_synapse_email_smtp_pass: ""
 matrix_synapse_email_smtp_require_transport_security: false
 matrix_synapse_email_notif_from: "Matrix <matrix@{{ matrix_domain }}>"
+matrix_synapse_email_app_name: Matrix
 matrix_synapse_email_client_base_url: "https://{{ matrix_server_fqn_element }}"
 matrix_synapse_email_invite_client_location: "https://app.element.io"
 

roles/custom/matrix-synapse/templates/synapse/homeserver.yaml.j2

@@ -2363,7 +2363,7 @@ email:
   # subjects. It defaults to 'Matrix'.
   #
   #app_name: my_branded_matrix_server
-  app_name: Matrix
+  app_name: {{ matrix_synapse_email_app_name | to_json }}
 
   # Uncomment the following to enable sending emails for messages that the user
   # has missed. Disabled by default.