Add etcd path prefix for all IAM assets (#8569)

Currently, we use the top-level prefix "config/"
for all our IAM assets, instead of to provide
tenant-level separation bring 'path_prefix'
to namespace the access properly.

Fixes #8567

cmd/config/etcd/help.go

@@ -26,9 +26,14 @@ var (
 			Description: `Comma separated list of etcd endpoints eg: "http://localhost:2379"`,
 			Type:        "csv",
 		},
+		config.HelpKV{
+			Key:         PathPrefix,
+			Description: `Default etcd path prefix to populate all IAM assets eg: "customer/"`,
+			Type:        "path",
+		},
 		config.HelpKV{
 			Key:         CoreDNSPath,
-			Description: `CoreDNS etcd path location to populate DNS srv records eg: "/skydns"`,
+			Description: `Default etcd path location to populate bucket DNS srv records eg: "/skydns"`,
 			Optional:    true,
 			Type:        "path",
 		},