[ANX] Change nonce to LongTimeNonceFactory

Migrate ANX to ValueFactory, use currentTimeMillis as nonce, just as before.

@timmolter I've removed `ANXUtils.nextNonce()` assuming it's not a public API. Let me know if you wanted it just marked `@deprecated`.

BTW, I've removed (c) and `@autor` from LongTimeNonceFactory.