This implementation will introduct changes to
the mod_quiz to implement the new qbank api
for view. Major changes are introduced in
the custom view and also all the legacy points
to the old qbank are changed to qbank plugins
where needed. It also deprecated and deletes
classes and scripts which were kept not to
break mod_quiz for the new api implementation.
This implementation will introduce a qbank plugin "tagquestion"
which will implement the tag question actions in the question
bank view by replacing the core class. Having this plugin
will give users the flexibility of enabling or
disabling this action.