[PP-1] Provide automated key rotation

In the context of OpenID Connect when using RS256 a "kid" is required on the JWKS endpoint and the header of the token.

If you try to pass the playground test with simple_oauth and this patch https://git.drupalcode.org/project/simple_oauth/-/merge_requests/171
It will complain about the "kid" being missing
https://openidconnect.net/

So the same kid needs to be in the JWKS endpoint and in the OpenIdConnectIdTokenResponse. I added one line there

    // Add required id_token claims.
     $builder = $this->getBuilder($accessToken, $userEntity);

     $builder = $builder->withHeader('kid', 'singlekey');
  

And I was able to go through all the steps in the playground