Add @task.kuberenetes_cmd

[insomnes]

Adding a new task flow decorator to run generated cmds in KubernetesPodOperator.

This decorator is based on the same idea as @task.bash: enrich Kubernetes pod command generation ability with simplified Python usage on the executor side to generate the command.
With the args_only option, the decorator would set the return value as arguments of the image entrypoint instead of rewriting the cmds.

This can significantly simplify usage for pure orchestrator cases and dynamic task mapping or generating the command from another task flow task result.

Changes:

• Add @task.kubernetes_cmd and register it in provider.yaml for cncf.kubernetes;
• Refactor @task.kubernetes unit tests to use the same base and have common tests with @task.kubernetes_cmd;
• Add @overload for @task.kubernetes description in decorators pyi file to enable proper doc-string and signature checking in IDEs
• System tests and docs example;

closes: #46414

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[insomnes]

Should I separate the test refactoring from this PR?

[insomnes]

The taskflow tutorial docs change docker -> cncf.kubernetes already applied in
#47387

[insomnes]

I think that this should be adjusted to use TaskSDK and not depend on direct DB access, so made it a draft for now, before I would understand the proper way of doing it.

[insomnes]

Updated based on the recent example of @task.bash decorator. Do not use the database session directly now.

I am still unsure: how to trigger system tests for example DAG in CI.

[potiuk]

Rebased it again - just to check - but I think this one will not get too much attention at least before RC1 - but please keep on rebasing it. Being on top of the main and fresh in the inbox helps.

[insomnes]

Rebased it again - just to check - but I think this one will not get too much attention at least before RC1 - but please keep on rebasing it. Being on top of the main and fresh in the inbox helps.

Yeah, I understand, there are a lot of things to do for the maintainers and committers now, and this PR is vast.
I am working on lowering the surface for it and also trying to rebase it from time to time.

Thank you!

[eladkal]

Temporary block till we sort out the decorators in providers