support site replication to replicate IAM users,groups (#14128)

- Site replication was missing replicating users,
  groups when an empty site was added.

- Add site replication for groups and users when they
  are disabled and enabled.

- Add support for replicating bucket quota config.

cmd/admin-bucket-handlers.go

@@ -65,7 +65,8 @@ func (a adminAPIHandlers) PutBucketQuotaConfigHandler(w http.ResponseWriter, r *
 		return
 	}
 
-	if _, err = parseBucketQuota(bucket, data); err != nil {
+	quotaConfig, err := parseBucketQuota(bucket, data)
+	if err != nil {
 		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
 		return
 	}
@@ -75,6 +76,21 @@ func (a adminAPIHandlers) PutBucketQuotaConfigHandler(w http.ResponseWriter, r *
 		return
 	}
 
+	bucketMeta := madmin.SRBucketMeta{
+		Type:   madmin.SRBucketMetaTypeQuotaConfig,
+		Bucket: bucket,
+		Quota:  data,
+	}
+	if quotaConfig.Quota == 0 {
+		bucketMeta.Quota = nil
+	}
+
+	// Call site replication hook.
+	if err = globalSiteReplicationSys.BucketMetaHook(ctx, bucketMeta); err != nil {
+		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
+		return
+	}
+
 	// Write success response.
 	writeSuccessResponseHeadersOnly(w)
 }