Store SSL key & cert in S3?

[wilb]

Given we can use S3 as a storage backend to a registry it feels like it would be nice to place my SSL cert & key in there too rather than having to mount a volume into the container.

Currently the simplest HA way I can see to achieve this at the moment is to embed the cert & key in another container and mount the volume, but this requires a private registry to deploy that container too so you end up in a catch 22 situation. Alternatively I need to deal with shared storage across the cluster, which I'd prefer to avoid...