Added watch script and chokidar (#5621)

# Pull Request

## 📖 Description

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What problem does this change solve?
Is this a breaking change, chore, fix, feature, etc?
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This PR adds `chokidar` so that we can watch files and re-run the playwright tests. Playwright does not currently have a watcher for this purpose so `chokidar-cli` was added to facilitate this.

## ✅ Checklist

### General

<!--- Review the list and put an x in the boxes that apply. -->

- [ ] I have included a change request file using `$ yarn change`
- [ ] I have added tests for my changes.
- [x] I have tested my changes.
- [ ] I have updated the project documentation to reflect my changes.
- [x] I have read the [CONTRIBUTING](https://github.com/Microsoft/fast/blob/master/CONTRIBUTING.md) documentation and followed the [standards](https://www.fast.design/docs/community/code-of-conduct/#our-standards) for this project.

packages/web-components/fast-ssr/package.json

@@ -23,6 +23,7 @@
     "prettier:diff": "prettier --config ../../../.prettierrc \"**/*.{ts,html}\" --list-different",
     "prettier": "prettier --config ../../../.prettierrc --write \"**/*.{ts,html}\"",
     "test": "playwright test --config=playwright.config.cjs",
+    "test:watch": "chokidar '**/*.spec.ts' -c 'npm run build && npm run test'",
     "test-server": "node server/dist/server.js",
     "install-playwright-browsers": "npx playwright install"
   },
@@ -39,6 +40,7 @@
     "@playwright/test": "^1.18.0",
     "@types/express": "^4.17.13",
     "@types/node": "^17.0.17",
+    "chokidar-cli": "^3.0.0",
     "express": "^4.17.1",
     "typescript": "^3.8.3"
   }