Opencast allows unauthorized public access via OAI-PMH

Opencast before 8.1 and 7.6 allows unauthorized public access to all media and metadata by default via OAI-PMH. OAI-PMH is part of the default workflow and is activated by default, requiring active user intervention of users to protect media. This leads to users unknowingly handing out public access to events without their knowledge. The problem has been addressed in Opencast 7.6 and 8.1 where the OAI-PMH endpoint is configured to require users with `ROLE_ADMIN` by default. In addition to this, Opencast 9 removes the OAI-PMH publication from the default workflow, making the publication a conscious decision users have to make by updating their workflows.