resolved: add SetLinkXYZ() method counterparts on the Link object

resolved: add SetLinkXYZ() method counterparts on the Link object

So far, we exposed SetLinkXYZ() on the Manager interface, to set a couple of link properties. This adds similar calls
SetXYZ() on the Link interface, and makes sure the former is little more than a shortcut to the latter.

SetLinkXYZ() has the benefit of not requiring a GetLink() round trip for setting these properties, while the method
actually belongs to the Link objects, and this change corrects that.