Refactor course_image_url

cms/djangoapps/contentstore/courseware_index.py

cms/djangoapps/contentstore/tests/test_utils.py

cms/djangoapps/contentstore/utils.py

cms/djangoapps/contentstore/views/course.py

cms/djangoapps/models/settings/course_details.py

common/djangoapps/util/parsing_utils.py

lms/djangoapps/bulk_email/tasks.py

lms/djangoapps/certificates/views/webview.py

lms/djangoapps/course_api/serializers.py

lms/djangoapps/course_structure_api/v0/serializers.py

lms/djangoapps/courseware/courses.py

lms/djangoapps/courseware/tests/test_courses.py

lms/djangoapps/courseware/tests/test_module_render.py

lms/templates/course.html

lms/templates/courseware/course_about.html

lms/templates/shoppingcart/receipt.html

lms/templates/shoppingcart/registration_code_receipt.html

lms/templates/shoppingcart/registration_code_redemption.html

lms/templates/shoppingcart/shopping_cart.html

openedx/core/djangoapps/content/course_overviews/models.py