Refresh id tokens

[nsklikas]

Describe the feature
It is not possible with the current implementation to issue ID tokens on refresh.

Additional context

The refresh token modifiers (https://github.com/oauthlib/oauthlib/blob/master/oauthlib/oauth2/rfc6749/grant_types/refresh_token.py#L66) take only 1 argument while the authorization code modifiers take 3 (https://github.com/oauthlib/oauthlib/blob/master/oauthlib/oauth2/rfc6749/grant_types/authorization_code.py#L308).

The modifier function add_id_token used to add id tokens in the OIDC token response is not compatible with the refresh token's modifier interface.

I see no reason to have that behavior. If there are no objections I can go ahead and create a PR that will harmonize the modifier arguments and add ID tokens to the refresh token responses for OIDC out of the box.

[thedrow]

Please do.