MDL-57678 core_course: Deprecate make_categories_options()
Padding nested course categories by space to make them render in a tree structure does not really make a lot of sense as they are already being rendered as full paths. It's simpler to show them without the indentation. Given this, there's not much point keeping make_categories_options(). So it's better to deprecate this function and call core_course_category::make_categories_list() directly instead.