[Apr 2025] - Add certificate to BucketAccess Secret

[BlaineEXE]

Enhancement

Is your feature request related to a problem?/Why is this needed

Especially on-prem object stores will likely have custom certificates that may not be signed by a well-known provider (may be self-signed).

Describe the solution you'd like in detail

Allow drivers to return a certificate that clients can use to auth the object storage server to COSI.

Describe alternatives you've considered

Admins always have the option to use other mechanisms for CA delivery. As such, this field should be optional.

Additional context

Originally proposed and discussed here: kubernetes/enhancements#4599 (comment)