Add new `permanentRedirect` function in App Router (#54047)
for internal:
https://vercel.slack.com/archives/C03S8ED1DKM/p1691700057242999
### Problem
- The existing [`redirect()`
function](https://nextjs.org/docs/app/api-reference/functions/redirect)
can't control the status code.
- The existing [`redirect()`
function](https://nextjs.org/docs/app/api-reference/functions/redirect)
returns a 307 HTTP redirect response while it returns a 308-equivalent
meta tag `<meta http-equiv="refresh" content="0;url=/foo"/>` in
streaming response (e.g., suspense boundary), making the behavior
inconsistent.
### Solution
Adding a new `permanentRedirect()` function and changing the meta tag
default accordingly.
| func | HTTP status | meta tag |
|---|:---:|---|
| `redirect()` | 307 | `<meta http-equiv="refresh"
content="1;url=/foo"/>` |
| `permanentRedirect()` | 308 | `<meta http-equiv="refresh"
content="0;url=/foo"/>` |
ref.
https://developers.google.com/search/docs/crawling-indexing/301-redirects
---------
Co-authored-by: JJ Kasper <jj@jjsweb.site>
Co-authored-by: Tim Neutkens <tim@timneutkens.nl>
Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>
