* Display "Top" categories in the category filter when listing questions in the question bank
* Prevent editing "Top" categories
* Prevent deleting "Top" categories
Changes include:
* question: Add bootstrap classes to buttons and selects so they look consistent.
* mod_quiz: Add bootstrap styles to report form elements
* question: Add bootstrap classes to question form elements
* And remove the success/fail styles from boost because they conflict badly
with the quiz plugin styles (making unreadable text).
* quiz: nav block buttons had black background
* quiz: Add bootstrap styles to quiz navigation buttons
* qtype_ddmarker: Remove bullets from list
Edit form coordinates preview had list bullets for each coordinate.
* boost: Prevent menu scrolling on quiz edit
* mod_quiz: Add bootstrap styles to edit quiz fields
Pagination and max grades forms.
* quiz: Undo some custom styles on review options
These checkboxes were laid out in a fake grid with no responsiveness
that conflicts with the bootstrap form-inline templates. Reset the
custom style to bootstrap default.
* quiz: Fix unit tests for boost changes
* qtype_ddwtos: Accurate positioning of drop targets
* questions: Make the review page responsive
* question: bootstrap 4 compatibility
.alert in bs4 contains no colours by default, you need to mix it with
one of the context classes to get some change in colours, borders etc.