allow multiple signature algorithms

[Dieken]

https://github.com/smallrye/smallrye-jwt/blob/main/implementation/jwt-auth/src/main/java/io/smallrye/jwt/config/JWTAuthContextInfoProvider.java#L224

    @Inject
    @ConfigProperty(name = "mp.jwt.verify.publickey.algorithm")
    private Optional<SignatureAlgorithm> mpJwtPublicKeyAlgorithm;

This should be Optional<Set<SignatureAlgorithm>> mpJwtPublicKeyAlgorithms, so that JWT tokens can smoothly switch to another algorithm.