7.1 remove old autorest (#785)

* init removal

* clean up warning

* bump ver to 7.1

* fix build

* custom http client no long supported

* cleanup unused types

* fix npe

* remove service client

* modern ssl settings

* fix test

* fix client cert null

* fix ctor

* cleanup

examples/attach/Attach.cs

@@ -2,7 +2,7 @@ using System;
 using System.Threading.Tasks;
 using k8s;
 using k8s.Models;
-using Microsoft.Rest;
+using k8s.Autorest;
 
 namespace attach
 {
@@ -10,8 +10,6 @@ namespace attach
     {
         private static async Task Main(string[] args)
         {
-            ServiceClientTracing.IsEnabled = true;
-
             var config = KubernetesClientConfiguration.BuildConfigFromConfigFile();
             IKubernetes client = new Kubernetes(config);
             Console.WriteLine("Starting Request!");