Detect multipart mime and ignore it

[gabriel-samfira]

Detect multipart mime user-data

This change makes ignition ignore user-data that is multipart mime.

How to use

Deploy a VM and add multipart mime userdata. If the VM boots, it works.

Testing done

Deployed a VM on OpenStack and set its userdata to a multipart mime userdata. The VM succeeded to boot.

• Changelog entries added in the respective changelog/ directory (user-facing change, bug fix, security fix, update)
• Inspected CI output for image differences: /boot and /usr size, packages, list files for any missing binaries, kernel modules, config files, kernel modules, etc.

Replaces: #823

/update-sdk

[github-actions]

Build action triggered: https://github.com/flatcar/scripts/actions/runs/5219795607

[pothos]

This needs a changelog entry and the commit IDs should point to merge commits, i.e., first merge the other PRs.

[gabriel-samfira]

This needs a changelog entry and the commit IDs should point to merge commits, i.e., first merge the other PRs.

I will gladly change the commits and add the changelog once the coreos-cloudinit and mantle PRs merge 😄. Just need some LGTMs on them.

[gabriel-samfira]

@krnowak changes made. Do you think it's worth running the test workflows again?

[krnowak]

@krnowak changes made.

Cool, thanks!

Do you think it's worth running the test workflows again?

Nah.