Add aggregatedAPIServerPort to the Concierge's static ConfigMap

- Allow the port number to be configured to any value within the
  range 1024 to 65535
- This commit does not include adding new config knobs to the ytt
  values file, so while it is possible to change this port without
  needing to recompile, it is not convenient

internal/concierge/server/server.go

@@ -168,6 +168,7 @@ func (a *App) runServer(ctx context.Context) error {
 		certIssuer,
 		buildControllers,
 		*cfg.APIGroupSuffix,
+		*cfg.AggregatedAPIServerPort,
 		scheme,
 		loginGV,
 		identityGV,
@@ -193,6 +194,7 @@ func getAggregatedAPIServerConfig(
 	issuer issuer.ClientCertIssuer,
 	buildControllers controllerinit.RunnerBuilder,
 	apiGroupSuffix string,
+	aggregatedAPIServerPort int64,
 	scheme *runtime.Scheme,
 	loginConciergeGroupVersion, identityConciergeGroupVersion schema.GroupVersion,
 ) (*apiserver.Config, error) {
@@ -207,7 +209,9 @@ func getAggregatedAPIServerConfig(
 	)
 	recommendedOptions.Etcd = nil // turn off etcd storage because we don't need it yet
 	recommendedOptions.SecureServing.ServerCert.GeneratedCert = dynamicCertProvider
-	recommendedOptions.SecureServing.BindPort = 8443 // Don't run on default 443 because that requires root
+
+	// This port is configurable. It should be safe to cast because the config reader already validated it.
+	recommendedOptions.SecureServing.BindPort = int(aggregatedAPIServerPort)
 
 	serverConfig := genericapiserver.NewRecommendedConfig(codecs)
 	// Note that among other things, this ApplyTo() function copies