Add Web Interface for wasm worker

[elijahmorg]

The current limbo web design is a bit complicated. #594 (comment)

Currently there is not a GOOD way to drive limbo from the main thread. This issue is for tracking the creation of an interface class that handles driving the limbo-worker via postmessage and onmessage actions while providing a clean and user friendly API.

This interface

1. Will be written in Typescript
2. Provide a clean API (nearly identical to sql.js / libsql) for actual database operations
3. handle initialization of web workers
4. be the entry point for npm package (index.js)