LB Source Ranges: Move validation into API layer

Had to move other things around too to avoid a weird api ->
cloudprovider dependency.

Also adding fixes per code reviews.

(This is a squash of the previously approved commits)

pkg/api/service/annotations.go

@@ -0,0 +1,28 @@
+/*
+Copyright 2016 The Kubernetes Authors 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 service
+
+const (
+	// AnnotationLoadBalancerSourceRangesKey is the key of the annotation on a service to set allowed ingress ranges on their LoadBalancers
+	//
+	// It should be a comma-separated list of CIDRs, e.g. `0.0.0.0/0` to
+	// allow full access (the default) or `18.0.0.0/8,56.0.0.0/8` to allow
+	// access only from the CIDRs currently allocated to MIT & the USPS.
+	//
+	// Not all cloud providers support this annotation, though AWS & GCE do.
+	AnnotationLoadBalancerSourceRangesKey = "service.beta.kubernetes.io/load-balancer-source-ranges"
+)