fix: #1131 - remove `kubectl` for `check` and `delete` operations

[BatmanAoD]

This is a partial implementation of #1131. It relies on https://github.com/infinyon/k8-api/pull/191. It only addresses two uses of kubectl, one for checking the k8s server version and one for deleting collections of objects.

I couldn't find valid Spec type definitions corresponding to SPU groups, persistent volume claims, or managed connectors. Each of these object types does have a ...Spec type defined, but they implement fluvio_stream_model::core::core_model::Spec rather than the required k8_types::spec_def::Spec. I'm guessing that these should implement both Spec traits, but I don't feel like I understand this part of the code well enough to dive in yet. Notably, it looks to me like SPU groups do have a valid Spec-implementing type, spg::k8::spec::K8SpuGroupSpec, but spg::k8 is a private module and it doesn't look like K8SpuGroupSpec is publicly re-exported anywhere.

I also found TableFormatSpec rather than TableSpec, so I'm not sure that's the right Spec to use, either.

[sehz]

nice progress

[github-actions[bot]]

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