Unify auth in a single AuthorizeDataVolume

[akalenyu]

Is your feature request related to a problem? Please describe:
Currently, operators utilizing CDI clone API need to "know a lot" about CDI clones
to do auth properly.
Kubevirt does this, for example:
https://github.com/kubevirt/kubevirt/blob/2baf5303dddfe71c98a2510357c464a8f7bdd3ca/pkg/virt-api/webhooks/validating-webhook/admitters/vms-admitter.go#L214-L275
(DataSource GET, Spec.PVC lookup)

Describe the solution you'd like:
We can try to unify auth in a single AuthorizeDataVolume:

• For DataSource GETs., we need to do something similar to https://github.com/kubevirt/kubevirt/blob/2baf5303dddfe71c98a2510357c464a8f7bdd3ca/pkg/virt-api/webhooks/validating-webhook/admitters/vms-admitter.go#L61-L67
• The DV should be passed to us so we could easily look up Spec.PVC
• For sources other than Source.PVC AuthorizeDataVolume is a no-op?

Describe alternatives you've considered:
A clear and concise description of any alternative solutions or features you've considered.

Additional context:
Add any other context or screenshots about the feature request here.

[aglitke]

/assign @akalenyu