cmd/k8s-operator,k8s-operator: operator integration tests (#12792)

This is the start of an integration/e2e test suite for the tailscale operator.
It currently only tests two major features, ingress proxy and API server proxy,
but we intend to expand it to cover more features over time. It also only
supports manual runs for now. We intend to integrate it into CI checks in a
separate update when we have planned how to securely provide CI with the secrets
required for connecting to a test tailnet.

Updates #12622

Change-Id: I31e464bb49719348b62a563790f2bc2ba165a11b
Co-authored-by: Irbe Krumina <irbe@tailscale.com>
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>

k8s-operator/conditions.go

@@ -167,3 +167,14 @@ func DNSCfgIsReady(cfg *tsapi.DNSConfig) bool {
 	cond := cfg.Status.Conditions[idx]
 	return cond.Status == metav1.ConditionTrue && cond.ObservedGeneration == cfg.Generation
 }
+
+func SvcIsReady(svc *corev1.Service) bool {
+	idx := xslices.IndexFunc(svc.Status.Conditions, func(cond metav1.Condition) bool {
+		return cond.Type == string(tsapi.ProxyReady)
+	})
+	if idx == -1 {
+		return false
+	}
+	cond := svc.Status.Conditions[idx]
+	return cond.Status == metav1.ConditionTrue
+}