Enable v1beta3 API via --runtime_config=api/v1beta3 flag

This exposes the proper v1beta3 API endpoint when the user specifies
the --runtime_config=api/v1beta3 argument to the apiserver. v1beta3
is still considered experimental and subject to change.

--runtime_config is a map of string keys and values, that can be
specified by providing

    --runtime_config=a=b,b=c,d,e

Only the key must be specified, the value can be omitted.

Enables v1beta3 in hack/local-up-cluster.sh and hack/test-cmd.sh

pkg/util/configuration_map.go

@@ -0,0 +1,53 @@
+/*
+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.
+*/
+
+package util
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+type ConfigurationMap map[string]string
+
+func (m *ConfigurationMap) String() string {
+	pairs := []string{}
+	for k, v := range *m {
+		pairs = append(pairs, fmt.Sprintf("%s=%s", k, v))
+	}
+	sort.Strings(pairs)
+	return strings.Join(pairs, ",")
+}
+
+func (m *ConfigurationMap) Set(value string) error {
+	for _, s := range strings.Split(value, ",") {
+		if len(s) == 0 {
+			continue
+		}
+		arr := strings.SplitN(s, "=", 2)
+		if len(arr) == 2 {
+			(*m)[arr[0]] = arr[1]
+		} else {
+			(*m)[arr[0]] = ""
+		}
+	}
+	return nil
+}
+
+func (*ConfigurationMap) Type() string {
+	return "mapStringString"
+}