This replaces the "Show question text in the question list?" filter, which was
never really a filter, with a new widget displayed alongside other question bank
controls like "Create a new question" and "Reset columns".
It also refactors the logic of displaying the question text field or not, so that
it is all handled within the qbank_viewquestiontext plugin rather than relying on
code in the view.
This implementation will introduce a qbank plugin "viewquestiontext"
which will view the question text row in the question bank view
by replacing the core class. Having this plugin will give users
the flexibility of enabling or disabling the question text row
in the question view.
Jun Pataleta