Add some relay-related variables to mautrix-slack role

roles/custom/matrix-bridge-mautrix-slack/templates/config.yaml.j2

@@ -113,12 +113,12 @@ bridge:
     relay:
         # Whether relay mode should be allowed. If allowed, the set-relay command can be used to turn any
         # authenticated user into a relaybot for that chat.
-        enabled: false
+        enabled: {{ matrix_mautrix_slack_bridge_relay_enabled | to_json }}
         # Should only admins be allowed to set themselves as relay users?
         # If true, non-admins can only set users listed in default_relays as relays in a room.
-        admin_only: true
+        admin_only: {{ matrix_mautrix_slack_bridge_relay_admin_only | to_json }}
         # List of user login IDs which anyone can set as a relay, as long as the relay user is in the room.
-        default_relays: []
+        default_relays: {{ matrix_mautrix_slack_bridge_relay_default_relays | to_json }}
         # The formats to use when sending messages via the relaybot.
         # Available variables:
         #   .Sender.UserID - The Matrix user ID of the sender.