Greenlight with OpenID

OPENID is now supported since greenlight 2.7.16 https://github.com/bigbluebutton/greenlight/blob/master/sample.env#L60

Roles are not supported see https://github.com/bigbluebutton/greenlight/issues/2696 - needs to be set in keycloak.

May require upgrade of DB see https://docs.bigbluebutton.org/greenlight/gl-config.html#upgrading-postgresql-versions