Global Source plugin

[Bluefinger]

Currently, there is a GlobalRng resource which accepts a generic parameter for plugging in a compatible RNG struct, though this might present problems for plugin authors as they won't be able to anticipate which RNG algorithm to use for seeding their own RNG sources.

Do we have to expose a concrete resource/component type in order for plugin authors to have a set target for getting entropy to seed their own sources? Or perhaps, plugin authors might need to declare that certain algorithms be used for meeting quality of entropy requirements. Therefore, we might need to re-export various algorithm libraries in order to provide the necessary types, though instead of adding all features by default, the re-exports are managed by features.