Pull submodule from upstream

[junghans]

Let's update submodule url to upstream where possible:

• boost -> https://github.com/boostorg/boost
• hdf5 -> https://github.com/HDFGroup
• hypre -> https://github.com/LLNL/hypre
• random123 -> https://github.com/DEShawResearch/Random123-Boost

[jbakosi]

Sure. But why did you pick that particular random123 fork?

@johnsalmon, is there a github repository for random123?

[junghans]

I meant https://github.com/DEShawResearch/Random123-Boost

[jbakosi]

https://github.com/DEShawResearch/Random123-Boost appears to be boost.random wrappers around Random123. I don't think it contains the actual Random123 library (only the wrappers), plus at this point we use the raw Random123 and not via boost.random. Even if we wanted to use Random123 via boost.random, it is also not clear to me how boost.random allows sampling from different threads for parallel random number generation, which is crucial.