Implementation of this IP: https://docs.openverse.org/projects/proposals/trust_and_safety/content_report_moderation/20240122-implementation_plan_bulk_moderation_actions.html

As part of the Sensitive Content Report Moderation project: https://docs.openverse.org/projects/proposals/trust_and_safety/content_report_moderation/20230411-project_proposal_content_report_moderation.html

Implements necessary models and views for enabling bulk moderation actions.