MDL-73335 question: Add the tertiary nav for question bank

The tertiary navigation has been added to the question bank.
- Url selector has been added for the pages:
  Questions, Categories, Import and Export
- A separate page to "Add category" has been added.
  The "Add category" is available as a tertiary nav button.
- Updated the tests for the changes made.

This commit is mostly Sujith's work, with further changes by
Tim Hunt <[email protected]> so we share the blame/credit.

AMOS BEGIN
 CPY [questioncats,mod_quiz],[questioncategories,core_question]
AMOS END

question/edit.php

@@ -52,7 +52,10 @@ echo $OUTPUT->header();
 
 // Print horizontal nav if needed.
 $renderer = $PAGE->get_renderer('core_question', 'bank');
-echo $renderer->extra_horizontal_navigation();
+
+// Render the selection action.
+$qbankaction = new \core_question\output\qbank_action_menu($url);
+echo $renderer->render($qbankaction);
 
 // Print the question area.
 $questionbank->display($pagevars, 'questions');