netstandard2 extendable lib model, basic rest (#793)

* first lib model

* add missing files

* happy test

* add vanilla rest for extend

* fix new url pattern

* address comments

* add v to tag

* bump ver

* add missing file when ren

* support multi pkg

* fix gh action

* fix env var

* ren title

* use gh action to set ver

* remove unused

* remove unused

examples/attach/Attach.cs

@@ -2,7 +2,6 @@ using System;
 using System.Threading.Tasks;
 using k8s;
 using k8s.Models;
-using k8s.Autorest;
 
 namespace attach
 {

examples/watch/Program.cs

@@ -3,7 +3,6 @@ using System.Threading;
 using System.Threading.Tasks;
 using k8s;
 using k8s.Models;
-using k8s.Autorest;
 
 namespace watch
 {

examples/yaml/Program.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.IO;
 using System.Threading.Tasks;
 using k8s;
 using k8s.Models;