Create a high-level explanation of how authentication and user provisioning work in RHDH and include this in the auth section of the docs (discuss with docs team on the best location to present this information)

• Cover the flow from user sign-in to user/group entity creation in the catalog
• Explain auth/catalog plugins involved, what roles they play, and how they interact with each other
• Ensure the content is understandable to new users and include diagrams if helpful