DelegatingAuthorizationOptions: exposes and sets a default timeout for SubjectAccessReview client

previously no timeout was set. Requests without explicit timeout might potentially hang forever and lead to starvation of the application.

cmd/kube-controller-manager/app/options/options_test.go

@@ -417,6 +417,7 @@ func TestAddFlags(t *testing.T) {
 		Authorization: &apiserveroptions.DelegatingAuthorizationOptions{
 			AllowCacheTTL:                10 * time.Second,
 			DenyCacheTTL:                 10 * time.Second,
+			ClientTimeout:                10 * time.Second,
 			RemoteKubeConfigFileOptional: true,
 			AlwaysAllowPaths:             []string{"/healthz"}, // note: this does not match /healthz/ or /healthz/*
 		},