ipfs/gateways: add breakdown by response code

[lidel]

This was discussed during IP Public Utilities WG Biweekly for 2024-06-06, cc @mishmosh @cewood @guillaumemichel

Missing information

https://probelab.io/ipfs/gateways/ is missing information about response status code distribution.

Where to find it

We should be able to export and read this information from Cloudflare source, similar to how we read daily edge request counts (fixed in #106).

For reference: sample distribution of response codes from Cloudflare)

How to represent it

We should start with basic "by status code" similar to "by region" one:

These stacked diagrams are already dynamic, clicking on the legend will allow hiding 410 and 403 and focusing on meaningful response codes like 200 499 or 504:

[guillaumemichel]

I'll get to it in the coming weeks