Chapel interface to random numbers

[npadmana]

It would be useful to have a Chapel interface to the random number generators (see comments from @LouisJenkinsCS here chapel-lang/chapel#12743).

Useful functionality would include:

• Simple wrappers for creating/cleaning up GSL random number generators, and accessing next numbers.
• Wrappers around common distributions (Gaussian, Poisson, what else)

[LouisJenkinsCS]

I think it should match Chapel's random module, but I really think that this should be cross-posted to chapel-lang/chapel/issues since we're more likely to get good feedback since we want it to essentially replace Chapel's standard (it could even become the new standard)