Replace golang-jwt with lestrrat-go/jwx

For the EUDI implementation, we needed JWK and JWE stuff etc, which we found in the `lestrrat-go/jwx` lib.
This causes some developer confusion, because we have existing JWT library `golang-jwt` in use for other JWT related code.

We'd like to unify all code to use the `lestrrat-go/jwx` library for JWT related code, as this offers more code we need.