feat: isolated contract execution environment

[ppedziwiatr]

Should be implemented as a separate library with an ExecutorFactory implementation.

First idea worth checking out is the https://github.com/laverdet/isolated-vm - but of course this will work only in a node env.

Other:
https://2021.esec-fse.org/details/fse-2021-papers/46/JSISOLATE-Lightweight-In-Browser-JavaScript-Isolation
https://www.semanticscholar.org/paper/TrustJS%3A-Trusted-Client-side-Execution-of-Goltzsche-Wulf/03a79b989b9852b8bf4bb77c54bf8d5124efeba6

or use WASM?
https://webassembly.org/docs/security/
https://developer.mozilla.org/pl/docs/WebAssembly
https://engineering.q42.nl/webassembly/ - very good analysis!
https://www.assemblyscript.org/
https://developer.mozilla.org/en-US/docs/WebAssembly/Using_the_JavaScript_API

[ppedziwiatr]

As a reminder - protection agains inf. loops in contract's code. Currently added protection (Promise.race) is not enough (but not much more can be done in case of pure JS).
In case of WASM - it should possible with the help of bytecodealliance/wasmtime#1490
krustlet/krustlet#223

[jsoneaday]

My vote is for Wasm. Since it would allow you guys not to have to create multiple implementations for different languages. And allow you to focus on core functionality instead.
It's fast, widely supported across languages and OS platforms, and continues to be developed with better features. Like Gpu, threading, garbage collection, and Simd support.

[ppedziwiatr]

Basic wasm support added in #101