[Feb 2025] - Support Read/Write/ReadWrite spec on COSI BucketAccesses (and classes?)

[BlaineEXE]

Enhancement

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

A common usage pattern of object storage is to have one applications with write (usually read-write, sometimes write-only) access to a bucket, and a separate application with read-only access to the same bucket.

COSI should support this usage pattern. This mirrors PVC access mode options, which can be used as prior art.
 
Describe the solution you'd like in detail

As long as the usage pattern is supported, design details are open for discussion and revision. Likely, this only applies to BucketAccess resources.

I anticipate that ReadOnly, WriteOnly, and ReadWrite are the minimal set of options COSI will need to implement.

ReadWriteExclusive and WriteOnlyExclusive modes might be worth considering, but enforcing ordering could be a problem. Consideration of these values might be best deferred for a future RFE.

Describe alternatives you've considered

COSI could rely on drivers to implement this themselves, but this is such a common and well-known pattern that there are benefits to having this as part of the COSI API.

Additional context