This will refactor code from the toolbar controllers to the views and factory.
The goal is to unify and reuse code for all views and store view specific logic within the views.

• Clean up EditableTemplatedWidget and implementations https://gerrit.wikimedia.org/r/#/c/298754/
• Introduce StructureEditorFactory https://gerrit.wikimedia.org/r/#/c/298755/
• Add getReferenceView https://gerrit.wikimedia.org/r/#/c/298757/
• Pass removeCallback to getStatementView https://gerrit.wikimedia.org/r/#/c/298758/
• Create all addtoolbars in ControllerViewFactory https://gerrit.wikimedia.org/r/#/c/298759/
• Switch reference removetoolbar https://gerrit.wikimedia.org/r/#/c/298760/
• Handle remove toolbars in ControllerViewFactory https://gerrit.wikimedia.org/r/#/c/298761/