kubernetes provider (#772)

* feat: Kubernetes ServiceDiscoveryProvider

* 编写k8s测试例子

* feat：fix kube config

* feat： remove port

* feat ： complete the k8s test

* feat :  add kubeserviceDiscovery test

* feat : add kube provider unittest

* feat :add kubetnetes docs

how to use ocelot with kubetnetes docs

* keep the configuration as simple as possible, no qos, no cache

* fix: use http

* add PollingKubeServiceDiscovery

* feat : refactor logger

* feat : add  pollkube docs

* feat：Remove unnecessary code

* feat ： code-block json

src/Ocelot.Provider.Kubernetes/KubeRegistryConfiguration.cs

@@ -0,0 +1,22 @@
+using KubeClient;
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Ocelot.Provider.Kubernetes
+{
+    public class KubeRegistryConfiguration
+    {
+        public Uri ApiEndPoint { get; set; }
+
+        public string KubeNamespace { get; set; }
+
+        public string KeyOfServiceInK8s { get; set; }
+
+        public KubeAuthStrategy AuthStrategy { get; set; }
+
+        public string AccessToken { get; set; }
+
+        public bool AllowInsecure { get; set; }
+    }
+}