Hercules Box

• hercules_rt crate defining HerculesBox type.
  • "Safe" interface for calling Hercules functions with collection inputs / outputs.
    • Safe with respect to ownership - can pass in shared / mutable slices into functions of CPU memory and it'll just do the right thing.
    • TODO: Not actually type safe, since it's non-trivial to encode Hercules types into Rust.
  • Internal methods for transferring internal state between immutable ref / mutable ref / owned memory.
    • TODO: Support moving between devices (in principle easy).

requested review from @prathi3

assigned to @rarbore2

mentioned in commit 9131736e

merged