Re-introduce the add layer short cut button in the map viewer

[allyoucanmap]

The new catalog implementation integration removed the quick button to add layers from the ActionNavbar.

It would be nice to re-introduce it as a shortcut and for consistency with previous version.

[stefanocudini]

re-add button titled: "add layer" for any resources, that simply open the new catalog to allow user to add documents,layers,maps