Refactor parser and serializer

[adambabik]

Highlights:

• Implement a new interface to communicate with VS Code.
• Add a renderer which outputs a formatted markdown (check out runme fmt).
• Better code organization.
• Promised-based interface in the WASM component.
• Switch to Go 1.19+.

Closes #64

[sourishkrout]

@adambabik tested with https://github.com/stateful/baldaquin/blob/main/README.md (internal repo). The enumerated list is being turned into a series of 1s... I know this might not be trivial but I wonder if it's possible to parse them as is (text) vs an enumerated list?

[adambabik]

@sourishkrout that was a bug. I fixed it in 11d6a8d#diff-66475d0028b5262e2fe42a3dbb02c34e6e37f7270b1925b15d764a52e0d529cfR116.

[sourishkrout]

I'd like to get this merged today (pending review stateful/vscode-runme#80) so we can "safely" merge and create pre-releases of runme/WASM without running the risk of release <> pre-release conflicts.

[adambabik]

@sourishkrout I can merge it now if you don't have any comments.

[sourishkrout]

@sourishkrout I can merge it now if you don't have any comments.

let's merge. however, there is still more testing & polish to be done so let's be sure to limit to pre-releases for now.