List all courses during OAut2/OpenID Connect

Previously, only courses respective to the branded instance were returned.

AN-3610
Merge pull request #5486 from rocha/list-all-visible-courses

Use all courses during OAut2/OpenID Connect
Reformat seq_module.py
Merge pull request #5474 from edx/openedx-jira-reference

Reformat seq_module.py
Changed default post type to discussion.