Warn if a Service with multiple ports is used

[WilliamDenniss]

kubehost has a documented limitation of only supporting services with a single port.

Until this is addressed, we should output a warning message if a service is given that has multiple ports.

Somewhere around here:

kubehost/kubehost

Lines 144 to 145 in 71d2a85

	declare -r service_port="$(kubectl get service ${service} -o=jsonpath='{.spec.ports[0].port}')"
	declare -r service_protocol="$(kubectl get service ${service} -o=jsonpath='{.spec.ports[0].protocol}')"