Clarify toolbar areas

[bergie]

Our toolbar has three button areas:

• Session buttons (Edit/Cancel, Save)
• Entity buttons (workflows, history, metadata)
• Property buttons (Hallo toolbar, Add)

Currently all widgets deal with the button areas in different ways. To be less coupled with the midgardToolbar widget, each of these should allow a selector to be used. This selector could then be passed in when instantiating Create or an individual widget. This way the widgets would be easier to integrate with CMSs that use custom toolbar implementations.

[flack]

WRT the toolbar widget, it would also be great if there was a way to programatically add or modify buttons. F.x. maybe I want to have a Logout button on the toolbar, it would be good if I could add it with something like

toolbar.addButton({label: 'Logout', href: '/LOGOUT'});