Allow defining inital admin credentials from outside

The initial admin credentials are hard-coded currently. We should turn them into settings that can be set form outside, e.g. from the Kubernetes secret store.

added Security part::backend type::feature labels

created merge request !514 (merged) to address this issue

mentioned in merge request !514 (merged)

closed with merge request !514 (merged)

mentioned in commit 1c949fe3