Make RS256 the default ID Token signature algorithm
A lot of OIDC applications fail with HS512 ID tokens, and having to set RS256 for ID tokens is very common error case when configuring OIDC RPs with LLNG.
Perhaps we should make RS256 the default for new RPs? It is the only required alg for OIDC OPs (see https://openid.net/specs/openid-connect-core-1_0.html#ServerMTI)