Shall we remove handmk3/4 coupling handlers?

[Nicogene]

Hands mk3 and mk4 become obsolete, the one mounted on the robots are the mk5 ones, we may remove the coupling handlers of those versions of hand.

cc @maggia80 @traversaro

[traversaro]

Ok, but we need also to remove the corresponding models from icub-models.

[maggia80]

Ok!