Support OIDC Authentication for the manager UI

[rbkaspr]

Just to start off, it's very nice to see that Pulsar has a native management and monitoring UI in the form of the pulsar-manager project.

That being said, from a user authentication perspective, I (and I think most enterprise) would love to see some sort of single sign-on (SSO) support, either in the form of LDAP federation or (preferable) OAuth2/OIDC to support things like RHSSO/Keycloak/Okta/etc for accessing the UI.