feat: detect bun as package manager

[kitop]

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Summary

As part of https://github.com/netlify/buildbot/issues/2912 and https://github.com/netlify/buildbot/issues/2914

Add detection of bun as a package manager. For that, we depend on a bun.lockb as documented in https://bun.sh/docs/install/lockfile.

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A picture of a cute animal (not mandatory, but encouraged)

[JGAntunes]

Just some small notes, looking good overall 🚀

[4xposed]

LGTM