refactor scheduler factory to use plugin architecture style like credentialprovider and cloudprovider for configuring priority functions and fit predicates

plugin/pkg/scheduler/algorithmprovider/plugins.go

@@ -0,0 +1,22 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// This package is used to register algorithm provider plugins.
+package algorithmprovider
+
+import (
+	_ "github.com/GoogleCloudPlatform/kubernetes/plugin/pkg/scheduler/algorithmprovider/defaults"
+)