Refactor configmap tests with common RabbitmqCluster and then modify properties as we need.

[ablease]

Similar to the stateful set tests were we have a common RabbitmqCluster generator. We could do something like this in the configmap tests too.

Neat pick: perhaps we can use generateRabbitmqCluster() and modify only the bits an pieces we want to test?

cluster-operator/internal/resource/statefulset_test.go

Lines 1572 to 1579 in 911ef0e

	func generateRabbitmqCluster() rabbitmqv1beta1.RabbitmqCluster {
	storage := k8sresource.MustParse("10Gi")
	return rabbitmqv1beta1.RabbitmqCluster{
	ObjectMeta: v1.ObjectMeta{
	Name: "foo",
	Namespace: "foo-namespace",
	},
	Spec: rabbitmqv1beta1.RabbitmqClusterSpec{

Something in the lines of:

instance = generateRabbitmqCluster()
instance.spec.ObjectMeta.Name = "rabbit-tls"
instance.spec.TLS.SecretName = "a-secret"
instance.spec.Rabbitmq.AdditionalPlugins = []rabbitmqv1beta1.Plugin{ ... }

Originally posted by @Zerpet in #451 (comment)