Add auto-update property to diagrams by default

[Riduidel]

Because it's painful to have to remember to set

	properties {
                "aadarchi.auto.update" "true"
            }

In each diagram.
And maybe add an Enhancer that would detect when diagrams have not the property set.

So, in archetype, there is a structurizr.dsl somewhere containing two diagrams. Add the property in each of these.