(bug 44745) Toolbar controller widget

Initialized in the repo's entityViewInit.js, the toolbar controller widget initializes
and manages all "add" and "edit" toolbars registered to the controller. This ensures
a clean separation between the toolbars and the actual widgets they interact with.

- patch set 2: Moved registry for toolbarcontroller definitions

Change-Id: If9537051448bc263ce749c0b56bba2a001c4b74f
Merge "(bug 44745) Toolbar controller widget"