Use multiple OIDC Client IDs for GFZ staging develop

Adds an own docker compose file for the staging develop deployment due to different environment variable name. There are ways to have less redundancy, but I think that should be part of another refactoring issue with lower priority. Anyway I opened an issue to discuss this: #59 (closed)

@marc.hanisch This should fix the post/upload issue on a local setup. I trust you reviewing it, so we could merge it asap.

@nils.brinckmann FYI (sry to spam your mailbox)

EDIT: The env-var GFZ_STAGING_DEVELOP_OIDC_CLIENT_IDS is set within this merge request and might also be double checked