[kuttl multinode] Disable router with gateways

With limited public IPs on some clouds we hit quota issues
from time to time.
So disabling router with gateway ports creation in kuttl
multinode jobs.

Same will be done on other jobs in follow up.

Related-Issue: #OSPCIX-771

Author: karelyatin

zuul.d/kuttl_multinode.yaml

@@ -15,6 +15,7 @@
             range: 192.168.122.0/24
             mtu: "{{ ('ibm' in nodepool.cloud) | ternary('1440', '1500') }}"
             router_net: "{{ ('ibm' in nodepool.cloud) | ternary('hostonly', 'public') }}"
+            router: false
           internal-api:
             vlan: 20
             range: 172.17.0.0/24