test/k8s: Add helpers to create Cilium services via CLI
test/k8s: Add helpers to create Cilium services via CLI

This adds helpers to invoke `cilium service update` and `cilium service
delete` via kubectl. It will be used to install IPv6 services for tests
on Kubernetes deployments that have not yet dual-stack mode enabled.

Signed-off-by: Sebastian Wicki <db043b2055cb3a47b2eb0b5aebf4e114a8c24a5a@isovalent.com>

cilium/cilium,tgraf/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,michi-covalent/cilium,cilium-team/cilium,tklauser/cilium,tgraf/cilium,cilium-team/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium