[dev-tool] add a command to extract api (Azure#27646)

if there are sub path exports, extract api for each of them; otherwise
extract a single report as before.

The output files by convention have the sub paths as their suffiex. For
example, `openai` would have the following api report output because it
has `.`, `./api`, `./rest`, `./models` sub path exports

>openai-..api.json
openai-.∕api.api.json
openai-.∕rest.api.json
openai-.∕models.api.json

These four files are then added into a zip, which could be uploaded to
apiview.dev once the support is added there.