Use RS256 instead of HS256 as the default OpenID Connect sign algorithm

[alextreme]

In a number of our projects we integrate OIDC (Azure, Keycloak, Signicat-DigiD, Signicat-eHerkenning). AFAIK for all of these integrations we need to set the OIDC sign algorithm from HS256 to RS256.

I'd like to propose that we set RS256 as the default

Auth0 also uses RS256 as default value:

https://community.auth0.com/t/jwt-signing-algorithms-rs256-vs-hs256/7720/3