Merge pull request #14767 from edx/andya/new-course-tab-preview

common/lib/xmodule/xmodule/tabs.py

lms/djangoapps/courseware/tabs.py

lms/djangoapps/courseware/tests/test_masquerade.py

lms/djangoapps/courseware/views/index.py

lms/djangoapps/courseware/views/views.py

lms/static/sass/course/layout/_courseware_preview.scss

lms/static/sass/shared-v2/_components.scss

lms/static/sass/shared-v2/_header.scss

lms/static/sass/shared-v2/_layouts.scss

lms/static/sass/shared-v2/_variables.scss

lms/templates/courseware/course_navigation.html

lms/templates/main.html

lms/templates/preview_menu.html

lms/templates/user_dropdown.html

openedx/core/djangoapps/plugin_api/views.py

openedx/features/course_bookmarks/views/course_bookmarks.py

...nce/templates/course_experience/course-home-fragment.html

...ures/course_experience/tests/views/test_course_outline.py

openedx/features/course_experience/urls.py

openedx/features/course_experience/views/course_home.py