Remove "Edit global site settings" button in sitetree view

Just talked with mitrasoft about ticket PRESIDECMS-455.
It may makes sense to remove the "Edit global site settings" button in the sitetree view.
Normally global settings are done once. The space can be used for a language dropdown (see related ticket). In addition it may confuses people when the click the button there and change settings they shouldn't be changed (only by an admin).