feat(fslib): add rmPromise/rmSync methods

[aduh95]

What's the problem this PR addresses?

The recursive option of rmdir is deprecated in Node.js. Unfortunately, because this lib doesn't expose the rm method, there's no alternative atm. This PR adds that alternative.

https://nodejs.org/api/deprecations.html#DEP0147

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How did you fix it?

I copied the rmdir implementations into a rm equivalent methods that calls in the fs.rm instead of fs.rmdir.
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Checklist

• I have read the Contributing Guide.

• I have set the packages that need to be released for my changes to be effective.

• I will check that all automated PR checks pass before the PR gets reviewed.

[RDIL]

LGTM