Add instructions on how to add authorized users

As an administrator installing Konveyor, I need guidance of how I may add/configure additional users for Konveyor.

See a conversation in slack from a user here:
https://kubernetes.slack.com/archives/CR85S82A2/p1678870757577409

This issue involves documenting guidance of how to interact with the underlying keycloak to add additional users

Start in the Konveyor documentation repository and locate the installation or administrator guidance relevant to adding users through the underlying Keycloak system. Document the steps needed to add or configure additional authorized users, using the linked Slack conversation for context; done means an administrator can follow the guidance successfully.

Written by the indexing model from the issue text.