Add script and instruction to build all the docker images by yourself

contrib/DockerFileBuildHelper/Extensions.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using YamlDotNet.RepresentationModel;
+
+namespace DockerFileBuildHelper
+{
+    public static class Extensions
+    {
+        public static YamlNode TryGet(this YamlNode node, string key)
+        {
+            try
+            {
+                return node[key];
+            }
+            catch (KeyNotFoundException) { return null; }
+        }
+    }
+}