show credit eligibility requirements in studio

cms/djangoapps/contentstore/views/course.py

...oapps/contentstore/views/tests/test_credit_eligibility.py

cms/djangoapps/models/settings/course_grading.py

cms/djangoapps/models/settings/course_metadata.py

cms/envs/common.py

cms/static/js/factories/settings.js

cms/static/js/models/settings/course_grading_policy.js

cms/static/js/views/settings/grading.js

cms/static/js/views/settings/main.js

cms/static/sass/views/_settings.scss

cms/templates/settings.html

cms/templates/settings_graders.html

common/test/acceptance/pages/studio/settings_advanced.py

openedx/core/djangoapps/credit/api.py

openedx/core/djangoapps/credit/signals.py

openedx/core/djangoapps/credit/tasks.py