Added utility to generate "_redirects" file

[dotansimha]

This new tool acts as a Webpack plugin to generate _redirects files (for CloudFlare Pages), based on NextJS redirects param.

Usage:

# next.config.js
import { applyUnderscoreRedirects } from 'guild-docs/underscore-redirects';

module.exports = {
  webpack(config, meta) {
    applyUnderscoreRedirects(config, meta);
    
    return config;
  },
}

[changeset-bot]

🦋 Changeset detected

Latest commit: 83f66ed

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
guild-docs	Minor

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Name	Status	Preview	Updated
the-guild-docs	✅ Ready (Inspect)	Visit Preview	Sep 4, 2022 at 9:01AM (UTC)

[github-actions]

📦 Next.js Bundle Analysis

This analysis was generated by the next.js bundle analysis action 🤖

This PR introduced no changes to the javascript bundle 🙌

[github-actions]

🚀 Snapshot Release (alpha)

The latest changes of this PR are available as alpha on npm (based on the declared changesets):

Package	Version	Info
guild-docs	4.1.0-alpha-20220904090056-0383800	npm ↗︎ unpkg ↗︎