RabbitMQ: set the max message processing time to 2 hours

Signed-off-by: Aurélien Bompard <aurelien@bompard.org>

roles/rabbitmq_cluster/templates/rabbitmq.conf.j2

@@ -90,6 +90,12 @@ cluster_formation.node_type = disc
 ##
 net_ticktime = 120
 
+# Maximum time for consumers to process and acknowledge messages (in ms)
+# Defaults to 30 minutes. Package signing in robosignatory can take more
+# than 1 hour, set the max to 2h.
+# https://www.rabbitmq.com/docs/consumers#acknowledgement-timeout
+consumer_timeout = 7200000
+
 
 ## Logging settings.
 ##