DELAY: add options for nanoseconds delay

I'd like to be able to inject delay in both incoming and outcoming messages, like with the existing DELAY protocol, but with a non-random amount in nanoseconds.

I initially thought to make new protocol but ended up proposing to add two new properties to the existing DELAY.

The nanoseconds options don't use a normal distribution but are added just as static constants.

For the existing random distribution, I've clarified that the range is meant as an upper bound but excluding the top value, and also changed it to use Random#nextInt(n)