Allow specifying custom bucket name or prefix in BucketClaim

[davtorrin]

Enhancement

The ability to specify a custom bucket name or prefix when creating a BucketClaim.

Currently, when creating a BucketClaim like this:

apiVersion: objectstorage.k8s.io/v1alpha1
kind: BucketClaim
metadata:
  name: bucket-claim-s3-test
spec:
  bucketClassName: cosi-s3-bucketclass
  protocols:
    - S3

The actual bucket created in the object storage backend follows a naming pattern like (e.g., cosi-s3-bucketclassa7f3d9k2).

While this ensures uniqueness, it lacks flexibility for organizations with strict naming conventions or integration requirements.

Why is this needed?:

Organizations require predictable bucket naming for compliance, governance, and integration with external systems. Current random naming prevents proper multi-tenancy isolation, audit traceability, and adherence to corporate naming policies.

Describe the solution you'd like in detail:

Add an optional bucketName or bucketPrefix field to the BucketClaim spec to allow users to customize the bucket name.

[BlaineEXE]

A custom bucketName will not be not allowed as an end-user configurable because it would allow too easy of an ability for users to "hijack" other buckets without admin control/oversight.

Administrators can create a bucket with a specific name manually and then create a COSI Bucket resource for it that users can reference using the static provisioning (brownfield) workflow.

A bucketPrefix is possible and something we can take under consideration for future COSI versions after v1alpha2.

I'll mark this as awaiting more evidence for now, and we will see what other community members think of the prefix proposal.