Migrate dependent goformation module to a local fork

[cheeseandcereal]

Description

This PR migrates away from using the goformation fork at https://github.com/weaveworks/goformation/tree/master.next to a 'local' fork within this repo under the goformation/ subdirectory.

The fork at weaveworks/goformation is really only used for this project, so maintaining a separate repo for a separate fork which requires manual updates adds complexity to the update process when releasing new features. Given that the upstream repository awslabs/goformation is archived, we are on our own for the maintenance of this fork, and shouldn't encourage its use elsewhere anyways.

Longer term, we may want to investigate alternatives to this dependent module/package, but for now, this just moves the dependency into the same repository here so we can more easily update it.

This PR also updates some of the golangci-lint config since it was using deprecated options; we are excluding goformation from being linted with the rest of the project.

I was able to build/run the tests/confirm everything is still working.

Checklist

• Added tests that cover your change (if possible)
• Added/modified documentation as required (such as the README.md, or the userdocs directory)
• Manually tested
• Made sure the title of the PR is a good description that can go into the release notes
• (Core team) Added labels for change area (e.g. area/nodegroup) and kind (e.g. kind/improvement)

BONUS POINTS checklist: complete for good vibes and maybe prizes?! 🤯

• Backfilled missing tests for code in same general area 🎉
• Refactored something and made the world a better place 🌟

[github-actions]

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[a-hilaly]

Great call, thanks Adam!