feat(codegen): use work items API in the parser codegen

What does this MR do and why?

feat(codegen): use work items API in the parser codegen

Behind a feature flag, we now use the work items API to fetch data.

How to set up and validate locally

1. Build wasm: wasm-pack build --target web
2. In the npm directory: npx wds.
3. Open the examples page on http://localhost:8000
4. The examples page has been modified to use work items now

Related to #46 (closed)