fix: use madmin.Credentials for gateway interface (#12493)

the main reason is to de-couple the project from
depending on MinIO's internal/auth package, other
changes will subsequently follow.

cmd/gateway/azure/gateway-azure.go

@@ -43,7 +43,6 @@ import (
 	"github.com/minio/madmin-go"
 	miniogopolicy "github.com/minio/minio-go/v7/pkg/policy"
 	minio "github.com/minio/minio/cmd"
-	"github.com/minio/minio/internal/auth"
 	"github.com/minio/minio/internal/logger"
 	"github.com/minio/pkg/bucket/policy"
 	"github.com/minio/pkg/bucket/policy/condition"
@@ -138,14 +137,14 @@ func (g *Azure) Name() string {
 }
 
 // NewGatewayLayer initializes azure blob storage client and returns AzureObjects.
-func (g *Azure) NewGatewayLayer(creds auth.Credentials) (minio.ObjectLayer, error) {
+func (g *Azure) NewGatewayLayer(creds madmin.Credentials) (minio.ObjectLayer, error) {
 	var err error
 
 	// Override credentials from the Azure storage environment variables if specified
 	if acc, key := env.Get("AZURE_STORAGE_ACCOUNT", creds.AccessKey), env.Get("AZURE_STORAGE_KEY", creds.SecretKey); acc != "" && key != "" {
-		creds, err = auth.CreateCredentials(acc, key)
-		if err != nil {
-			return nil, err
+		creds = madmin.Credentials{
+			AccessKey: acc,
+			SecretKey: key,
 		}
 	}
 
@@ -244,11 +243,6 @@ func parseStorageEndpoint(host string, accountName string) (*url.URL, error) {
 	return url.Parse(endpoint)
 }
 
-// Production - Azure gateway is production ready.
-func (g *Azure) Production() bool {
-	return true
-}
-
 // s3MetaToAzureProperties converts metadata meant for S3 PUT/COPY
 // object into Azure data structures - BlobMetadata and
 // BlobProperties.