Add docs on how to migrate from Create React App. #17454

[peppermint-juli]

Addresses #17454

[ijjk]

Stats from current PR

Default Server Mode (Increase detected ⚠️)

General

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
buildDuration	13.4s	13.5s	⚠️ +120ms
nodeModulesSize	63.1 MB	63.1 MB	✓

Page Load Tests Overall increase ✓

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
/ failed reqs	0	0	✓
/ total time (seconds)	2.575	2.548	-0.03
/ avg req/sec	971.05	981.33	+10.28
/error-in-render failed reqs	0	0	✓
/error-in-render total time (seconds)	1.518	1.446	-0.07
/error-in-render avg req/sec	1647.21	1729	+81.79

Client Bundles (main, webpack, commons)

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
677f882d2ed8..9339.js gzip	10.9 kB	10.9 kB	✓
framework.HASH.js gzip	39 kB	39 kB	✓
main-d493e7d..42f5.js gzip	7.17 kB	7.17 kB	✓
webpack-e067..f178.js gzip	751 B	751 B	✓
Overall change	57.8 kB	57.8 kB	✓

Client Bundles (main, webpack, commons) Modern

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
677f882d2ed8..dule.js gzip	6.77 kB	6.77 kB	✓
framework.HA..dule.js gzip	39 kB	39 kB	✓
main-f8905d4..dule.js gzip	6.24 kB	6.24 kB	✓
webpack-07c5..dule.js gzip	751 B	751 B	✓
Overall change	52.7 kB	52.7 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
polyfills-4b..e242.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
_app-9a0b9e1..b37e.js gzip	1.28 kB	1.28 kB	✓
_error-ed1b0..8fbd.js gzip	3.44 kB	3.44 kB	✓
hooks-89731c..c609.js gzip	887 B	887 B	✓
index-17468f..5d83.js gzip	227 B	227 B	✓
link-d2344ce..8b36.js gzip	1.3 kB	1.3 kB	✓
routerDirect..924c.js gzip	284 B	284 B	✓
withRouter-7..c13d.js gzip	284 B	284 B	✓
Overall change	7.71 kB	7.71 kB	✓

Client Pages Modern

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
_app-75d3a82..dule.js gzip	625 B	625 B	✓
_error-4469a..dule.js gzip	2.29 kB	2.29 kB	✓
hooks-cbf13f..dule.js gzip	387 B	387 B	✓
index-b9a643..dule.js gzip	226 B	226 B	✓
link-f8c0daf..dule.js gzip	1.26 kB	1.26 kB	✓
routerDirect..dule.js gzip	284 B	284 B	✓
withRouter-f..dule.js gzip	282 B	282 B	✓
Overall change	5.36 kB	5.36 kB	✓

Client Build Manifests

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
_buildManifest.js gzip	322 B	322 B	✓
_buildManife..dule.js gzip	329 B	329 B	✓
Overall change	651 B	651 B	✓

Rendered Page Sizes

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
index.html gzip	1 kB	1 kB	✓
link.html gzip	1.01 kB	1.01 kB	✓
withRouter.html gzip	996 B	996 B	✓
Overall change	3.01 kB	3.01 kB	✓

---

Serverless Mode

General

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
buildDuration	15s	15.1s	⚠️ +73ms
nodeModulesSize	63.1 MB	63.1 MB	✓

Client Bundles (main, webpack, commons)

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
677f882d2ed8..9339.js gzip	10.9 kB	10.9 kB	✓
framework.HASH.js gzip	39 kB	39 kB	✓
main-d493e7d..42f5.js gzip	7.17 kB	7.17 kB	✓
webpack-e067..f178.js gzip	751 B	751 B	✓
Overall change	57.8 kB	57.8 kB	✓

Client Bundles (main, webpack, commons) Modern

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
677f882d2ed8..dule.js gzip	6.77 kB	6.77 kB	✓
framework.HA..dule.js gzip	39 kB	39 kB	✓
main-f8905d4..dule.js gzip	6.24 kB	6.24 kB	✓
webpack-07c5..dule.js gzip	751 B	751 B	✓
Overall change	52.7 kB	52.7 kB	✓

Legacy Client Bundles (polyfills)

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
polyfills-4b..e242.js gzip	31 kB	31 kB	✓
Overall change	31 kB	31 kB	✓

Client Pages

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
_app-9a0b9e1..b37e.js gzip	1.28 kB	1.28 kB	✓
_error-ed1b0..8fbd.js gzip	3.44 kB	3.44 kB	✓
hooks-89731c..c609.js gzip	887 B	887 B	✓
index-17468f..5d83.js gzip	227 B	227 B	✓
link-d2344ce..8b36.js gzip	1.3 kB	1.3 kB	✓
routerDirect..924c.js gzip	284 B	284 B	✓
withRouter-7..c13d.js gzip	284 B	284 B	✓
Overall change	7.71 kB	7.71 kB	✓

Client Pages Modern

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
_app-75d3a82..dule.js gzip	625 B	625 B	✓
_error-4469a..dule.js gzip	2.29 kB	2.29 kB	✓
hooks-cbf13f..dule.js gzip	387 B	387 B	✓
index-b9a643..dule.js gzip	226 B	226 B	✓
link-f8c0daf..dule.js gzip	1.26 kB	1.26 kB	✓
routerDirect..dule.js gzip	284 B	284 B	✓
withRouter-f..dule.js gzip	282 B	282 B	✓
Overall change	5.36 kB	5.36 kB	✓

Client Build Manifests

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
_buildManifest.js gzip	322 B	322 B	✓
_buildManife..dule.js gzip	329 B	329 B	✓
Overall change	651 B	651 B	✓

Serverless bundles

	vercel/next.js canary	PeppermintNDaisies/next.js migrating-from-create-react-app	Change
_error.js	1.05 MB	1.05 MB	✓
404.html	4.34 kB	4.34 kB	✓
hooks.html	3.92 kB	3.92 kB	✓
index.js	1.05 MB	1.05 MB	✓
link.js	1.1 MB	1.1 MB	✓
routerDirect.js	1.09 MB	1.09 MB	✓
withRouter.js	1.09 MB	1.09 MB	✓
Overall change	5.4 MB	5.4 MB	✓

Commit: a71e122

[leerob]

Thank you so much for helping out here! This ended up being a lot more work than I expected, which has turned into #21212. We'll be moving forward with that PR, but greatly appreciate your efforts to contribute here 🙏