CryptoHelper needs a Home

https://github.com/GJWT/javaOIDCMsg/blob/cbdf7aa5be7896a7958e55b2ac2dda0a0956adda/lib/src/main/java/com/auth0/jwt/algorithms/CryptoHelper.java#L26

CryptoHelper needs a more extensible setup and a better home. Pick static or instantiable based off whichever makes more sense, but make an informed call.