Set request timeouts for the thread pools

The request timeout should ensure that the operations don't back up if the
thread pool is overloaded.

scripts/guix-data-service.in

@@ -214,7 +214,10 @@
                                    2))
                          #:idle-seconds 60
                          #:idle-thunk
-                         close-thread-postgresql-connection)))
+                         close-thread-postgresql-connection))
+
+                       (thread-pool-request-timeout 10))
+
                     (start-guix-data-service-web-server
                      (assq-ref opts 'port)
                      (assq-ref opts 'host)