Add ability to disable password auth

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

@@ -2241,7 +2241,7 @@ sso:
 password_config:
    # Uncomment to disable password login
    #
-   #enabled: false
+   enabled: {{ matrix_synapse_password_config_enabled|to_json }}
 
    # Uncomment to disable authentication against the local password
    # database. This is ignored if `enabled` is false, and is only useful