Converted Hierachy provisioning and extraction to async

[danielpastoor]

I have converted the hierachy handlers to async and added a overload for ApplyTenantTemplate so that it is still posible to call it not async.

The reason why I did this is because if had problems with the creation of the graph client.

And also I'm not a big fan of the .GetAwaiter() function as it fakes the await and can give some problemes.