Deprecate config-dir bring in certs-dir for TLS configuration (#7033)

This PR is to provide indication that config-dir will be removed
in future and all users should migrate to new --certs-dir option

Fixes #7016
Fixes #7032

cmd/gateway-main.go

@@ -124,16 +124,13 @@ func StartGateway(ctx *cli.Context, gw Gateway) {
 	// To avoid this error situation we check for port availability.
 	logger.FatalIf(checkPortAvailability(globalMinioPort), "Unable to start the gateway")
 
-	// Create certs path.
-	logger.FatalIf(createConfigDir(), "Unable to create configuration directories")
-
 	// Check and load TLS certificates.
 	var err error
 	globalPublicCerts, globalTLSCerts, globalIsSSL, err = getTLSConfig()
 	logger.FatalIf(err, "Invalid TLS certificate file")
 
 	// Check and load Root CAs.
-	globalRootCAs, err = getRootCAs(getCADir())
+	globalRootCAs, err = getRootCAs(globalCertsCADir.Get())
 	logger.FatalIf(err, "Failed to read root CAs (%v)", err)
 
 	// Handle common env vars.