Document type builder withDefaultTemplate takes a string, but should be bool

[nikolajlauridsen]

On the document type builder we have a method withDefaultTemplate(alias : string), however when experimenting around I found that this only works if the alias you supply is the same as the doc type, so it doesn't really makes sense to take a string.

Instead I think we should make it a bool, and if it's true just set the default template alias to be the alias of the doc type when building