Clarify audience value in Concierge-only auth doc, and other doc updates

Also renamed a couple of integration test files to make their names
more clear.

test/integration/smoke_test.go

@@ -0,0 +1,24 @@
+// Copyright 2020-2023 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package integration
+
+import (
+	"os"
+	"os/exec"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"go.pinniped.dev/test/testlib"
+)
+
+// Smoke test to see if the kubeconfig works and the cluster is reachable.
+func TestGetNodes(t *testing.T) {
+	_ = testlib.IntegrationEnv(t)
+	cmd := exec.Command("kubectl", "get", "nodes")
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err := cmd.Run()
+	require.NoError(t, err)
+}