adding random_iterator

Dear colleagues,

This merge request introduces random_iterator library in corsika. The main changes are that:

1. From now only a single seed is set for every corsika job.
2. The registered streams are running on substream parallelism configuration
3. RNGManager now is template<typename CBPRNG=random_iterator::philox> RNGManager;

There are many other details, but all is adjusted now and should be working fine.

Please, can you review this and let me know if everything is ok?