Enhancement: Ignore `s3.storage-class` archive tiers for metadata

Restic used to store all files on S3 using the specified `s3.storage-class`.

Now, restic will only use non-archive storage tiers for metadata, to avoid
problems when accessing a repository. To restore any data, it is still
necessary to manually warm up the required data beforehand.

NOTE: There is no official cold storage support in restic, use this option at
your own risk.

https://github.com/restic/restic/issues/4583
https://github.com/restic/restic/pull/4584
