Add custom policy claim name (#8764)

In certain organizations policy claim names
can be not just 'policy' but also things like
'roles', the value of this field might also
be *string* or *[]string* support this as well

In this PR we are still not supporting multiple
policies per STS account which will require a
more comprehensive change.

cmd/config/identity/openid/help.go

@@ -32,9 +32,15 @@ var (
 			Type:        "string",
 			Optional:    true,
 		},
+		config.HelpKV{
+			Key:         ClaimName,
+			Description: `JWT canned policy claim name, defaults to "policy"`,
+			Optional:    true,
+			Type:        "string",
+		},
 		config.HelpKV{
 			Key:         ClaimPrefix,
-			Description: `JWT claim namespace prefix e.g. "customer1"`,
+			Description: `JWT claim namespace prefix e.g. "customer1/"`,
 			Optional:    true,
 			Type:        "string",
 		},