During development of #22428 we decided that we have
no need for `object-storage.yaml`, and we'd rather store
the endpoints in `scylla.yaml` and get a REST api to exopose
the endpoints for free.
This patch removes the credentials provider used to read the
aws keys from this yaml file.
Followup work will remove the `object-storage.yaml` file
altogether and move the endpoints to `scylla.yaml`.
Signed-off-by: Robert Bindar <robert.bindar@scylladb.com>
Closesscylladb/scylladb#22951