Feat: Add fs-extra

[walter-0]

Closes (#126)

Snippets to add:

• emptyDir
• emptyDirSync
• ensureFile
• ensureFileSync
• ensureLink
• ensureLinkSync
• ensureSymlink
• ensureSymlinkSync
• outputFile
• outputFileSync
• outputJson
• outputJsonSync
• pathExists
• readJson
• readJsonSync
• writeJson
• writeJsonSync

[pralkarz]

Since fs.exists is deprecated, I think we should suggest either using the synchronous version (fs.existsSync) or inlining what fs-extra does (and Node docs recommend): fs.access().then(() => true).catch(() => false).

[walter-0]

Hey @ziebam thanks a lot for the comments! My intent for this PR was mostly to get fs-extra merged in so that I can start making a codemod that covers everything (since additions to module-replacements-codemods require an entry in this repo first), and not as a complete migration guide. If this is ok as an initial, then more detail/snippets can be added to this doc so I can work on a codemod concurrently.

[43081j]

I'll have a full read through in the next day or so. But from a quick scan through it, I think we should do a few of the PR comments at least since they're about which method to prefer.

I don't think we need a migration guide, but we should at least mention the basic mappings (old to new/replacement)