getProviders should be callable from a server component

[pippinmole]

Goals

1. Allow for getProviders() from next-auth/react to be used server side.

Non-Goals

No response

Background

Currently, you are forced to use getProviders client-side through by either:

• Using getServerSideProps (which isn't applicable to app router)
• Using the use() API like so: const providers = use(getProviders())
• Using useEffect

I think we should be able to use this function server side to reduce the 'time-to-providers'. I don't see why a login page has to asynchronously load in the providers on the client side.

Proposal

Allow for this syntax:

import {getProviders} from "next-auth/react";

export default async function Index() {
  // this is a server component
  const providers = await getProviders()

  return <>
    {providers &&
      Object.values(providers).map((provider) => (
        <p>{provider.name}</p>
      ))}
  </>
}

currently, if you try to render this component, you'll get this error:

 ⨯ app\page.tsx (4:38) @ getProviders
 ⨯ TypeError: (0 , next_auth_react__WEBPACK_IMPORTED_MODULE_1__.getProviders) is not a function
    at Index (./app/page.tsx:11:90)
    at stringify (<anonymous>)

this is of course expected, since the function isn't exported in any way to the server build.