Move resgen artifacts from submodules into src subfolders

Submodule adds unnessesary complexity.
This commit removes dependency on pre-generated C# bindings.
Start-PsBuild -ResGen will call Start-ResGen.
It also has auto-detect logic to simplify first time expirience.

.gitignore

@@ -30,3 +30,6 @@ powershell.version
 
 # default location for produced nuget packages
 /nuget-artifacts
+
+# resgen output
+gen