Replace image validity check with shell script

[twz123]

Description

The script is more or less straight forward and saves us some go dependencies and a custom go build execution.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update

How Has This Been Tested?

• Manual test
• Auto test added

Checklist:

• My code follows the style guidelines of this project
• My commit messages are signed-off
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules
• I have checked my code and corrected any misspellings

[twz123]

On the other hand, is this functionality still useful? K0s ships its own images anyways, so it's under the project's control to provide appropriate multi-arch images anyways. We could simply remove it?

[jnummelin]

We could simply remove it?

I wonder would we catch any missing archs in smokes? For most of the images probably yes, but we're not really running with all permutation configs for arm/arm64 smokes that would exercise all the images.

[twz123]

My point here is that the default images are all built by the k0s project. How likely is it that we're forgetting to ship an architecture? I guess this was a bigger concern back in the day when k0s used upstream images verbatim.

[twz123]

Plus, wouldn't the airgap image tarball generation fail when an image is unavailable for a certain architecture?

[jnummelin]

How likely is it that we're forgetting to ship an architecture?

Quite low I'd say

wouldn't the airgap image tarball generation fail when an image is unavailable for a certain architecture?

I think you're right, it would AFAIK fail.

So maybe we should just remove this stuff

[twz123]

Superseded by #3913.