Add AST info capability

[ryyppy]

We'd like to explore a way to be able to render a simple AST explorer on the playground interface. We may take some parts of what the ocaml-vscode extension uses (ppx_tools dumpast), adapt it to our needs and render the specific AST in a custom tab on the rescript-lang playground website.

See: https://github.com/ocamllabs/vscode-ocaml-platform/blob/master/src/ast_editor.ml

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[fhammerschmidt]

could still be interesting

[nojaf]

Yes, would having the output of rescript-tools doc be beneficial?