Implement DeleteAllOf in blockingcacheclient and pluginhookclient

[behrooz]

What does this PR do?

Implements DeleteAllOf explicitly on the wrapper clients so the previously unimplemented method is no longer a TODO.

Changes

• pkg/util/blockingcacheclient/client.go: Add DeleteAllOf that delegates to the embedded client.Client. Removes the // TODO: implement DeleteAllOf comment.
• pkg/util/pluginhookclient/client.go: Add DeleteAllOf that delegates to the embedded client.Client. Removes the // TODO: implement DeleteAllOf comment.

Behavior

No behavior change. Both wrappers already exposed the embedded client’s DeleteAllOf via struct embedding. This makes that behavior explicit and resolves the TODOs.

[flomedja]

As you said both structs already get DeleteAllOf promoted from their embedded client.Client field. If we want to implement DeleteAllOf to be compliant with the Delete implementation that will require cache-blocking and check for pluginHooks on a group of objects present in the cache.
IMHO just calling the wrapped function have no real value however I agree that we could make the TODO comment more explicit for a future implementation.

WDYT @FabianKramm

[FabianKramm]

Totally agree here @flomedja, this PR doesn't really improve the situation.