Added interface for auth proxy egress settings
partially addresses: https://gitlab.developers.cam.ac.uk/uis/devops/ssgw/deploy/-/issues/35
GitLab will be upgraded on 28/03/2024 between 12:00 and 14:00. There may be small periods of service instability.
partially addresses: https://gitlab.developers.cam.ac.uk/uis/devops/ssgw/deploy/-/issues/35