MDL-40431 libraries: deprecate get_context_url()
MDL-40431 libraries: added another PHPUnit test to ensure deprecated function returns the same as the replacement
MDL-40462 libraries: deprecate get_course_context()
MDL-40462 libraries: added another PHPUnit test to ensure deprecated function returns the same as the replacement
MDL-40464 libraries: Deprecate get_user_courses_bycap()
MDL-40467 Libraries: get_role_context_caps should not be deprecated

Even though there is no use of get_role_context_caps function in core, it should
not be depecated, as there is no alternate method to get role capability in context