Serde support for (rusty_)v8
WIP: see denoland/deno#9540
- Experiment with KeyCache to optimize struct keys
- Experiment with external v8 strings
- Explore using json-stringifier.cc's fast-paths for arrays
- Improve tests to test parity with
serde_json(should be mostly interchangeable) - Consider a
Payloadtype that's deserializable by itself (holds scope & value) - Ensure we return errors instead of panicking on
.unwrap()s