Rename iam/validator -> iam/openid and add tests (#8340)

Refactor as part of config migration

cmd/globals.go

@@ -33,8 +33,8 @@ import (
 	"github.com/minio/minio/pkg/auth"
 	"github.com/minio/minio/pkg/certs"
 	"github.com/minio/minio/pkg/dns"
+	"github.com/minio/minio/pkg/iam/openid"
 	iampolicy "github.com/minio/minio/pkg/iam/policy"
-	"github.com/minio/minio/pkg/iam/validator"
 	"github.com/minio/minio/pkg/pubsub"
 )
 
@@ -269,7 +269,7 @@ var (
 	standardExcludeCompressContentTypes = []string{"video/*", "audio/*", "application/zip", "application/x-gzip", "application/x-zip-compressed", " application/x-compress", "application/x-spoon"}
 
 	// Authorization validators list.
-	globalIAMValidators *validator.Validators
+	globalIAMValidators *openid.Validators
 
 	// OPA policy system.
 	globalPolicyOPA *iampolicy.Opa