Button on mcore diagram editor, which removes all unneeded labels and arities

In all our methodologies, we do not show names of properties when they are the same as the type name.

As well, for containment properties, [0..*] is the usual case, and for non-containment it is [1..1].

Currently, we do remove this unneeded label by hand, in a lenthy process to "craft" diagrams.

A button shall automate this, by removing them automatically from a diagram.