feat: Add experimental debug container command

[nightkr]

Description

Adds a stackablectl experimental-debug command that creates and attaches a debug container. Compared to kubectl debug it should also (at least) mount in volumes and environment variables from the container being debugged.

Fixes #201.

Definition of Done Checklist

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Author

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1. Changes are OpenShift compatible

Reviewer

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1. Code contains useful comments
2. (Integration-)Test cases added
3. Documentation added or updated
4. Changelog updated
5. Cargo.toml only contains references to git tags (not specific commits or branches)

Acceptance

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1. Feature Tracker has been updated
2. Proper release label has been added

Once the review is done, comment bors r+ (or bors merge) to merge. Further information

[nightkr]

• Create container
• Attach
• Fall back to pulling logs if attach fails (maybe?)
• Clean up stdin
• Docs

[nightkr]

This is intentionally not part of the cockpit library since it's experimental and assumes that it's running in its own TTY. It could be factored out into a library component but I don't think it's super valuable to do preemptively.

[NickLarsenNZ]

@nightkr, forgive my meddling. Was just trying to get the workflows to pass, so I added a couple of commits which were ultimately unnecessary as I backported some other changes to main which required those same two changes for the workflow to pass (I think). So, those two changes came in via the latest merge.

[Techassi]

First round, mostly looking good!