Handle error 429 and `Retry-After` header

[severo]

See #213 (comment) and #213 (comment)

When receiving error 429 when fetching Parquet data, we could:

• read the Retry-After header if present, otherwise use a default retry delay
• wait for this delay then retry
• show a temporary error message (toast?). If we identify that the source is Hugging Face (only in https://github.com/hyparam/space for now), we could propose to login if it's not already the case, because passing a token raises the rate limiting threshold.

[severo]

Note that hyperparam fetches the data from a web worker. We pass from to the worker through a message, but it's not possible to pass a function. So: the custom fetch function (like https://www.npmjs.com/package/fetch-retry) should be defined in the worker. Possibly some parameters (default retry delay, etc) could be passed in the message if needed

As an alternative, the worker could send details about the error (429 + retry-after if any), and let the client control the flow of fetches.

In either ways, it's not trivial.

[severo]

Also, I reproduced the issue:

1. launch npm run dev
2. enter http://localhost:5173/?key=https://huggingface.co/datasets/HuggingFaceFW/fineweb/resolve/main/data/CC-MAIN-2013-20/000_00000.parquet
3. open the network panel in the developer tools
4. sort along the language column

In my test, it created 2,184 requests, and about 150 of them are CORS errors, i.e., no response, no 429 code, and no Retry-After header. Not easy to handle.