Add WSL (#1081)

* Add WSL

* Move WSL to the end of the provision

* Add elevated_user

* No restart VM

* Add Validation

* Add WSL note in Readme.md

* Rename WSL1 to WSL

Co-authored-by: Sergey Dolin <v-sedoli@micorosoft.com>

images/win/Windows2019-Azure.json

@@ -109,6 +109,14 @@
             ],
             "execution_policy": "unrestricted"
         },
+        {
+            "type": "powershell",
+            "elevated_user": "SYSTEM",
+            "elevated_password": "",
+            "scripts":[
+                "{{ template_dir }}/scripts/Installers/Windows2019/Install-WSL.ps1"
+            ]
+        },
         {
             "type": "powershell",
             "scripts":[
@@ -243,6 +251,12 @@
                 "{{ template_dir }}/scripts/Installers/Validate-Wix.ps1"
             ]
         },
+        {
+            "type": "powershell",
+            "scripts":[
+                "{{ template_dir }}/scripts/Installers/Validate-WSL.ps1"
+            ]
+        },
         {
             "type": "powershell",
             "scripts":[
@@ -1062,4 +1076,4 @@
             ]
         }
     ]
-}
+}