This adds benchmarks from lib sodium, but the results are hard to interpret. We may need to recompile them using zig so that we can export a function instead of using WASI to do it. Right now, we can't really see performance of functions because other runtimes aren't designed to re-instantiate like ours.
This only compares against wasmtime as that's the only runtime besides
ours that is safe to re-instantiate.
Signed-off-by: Adrian Cole <adrian@tetrate.io>