ipfs/gateways: add breakdown by domain name

[lidel]

This is similar to #107 but per DNS Zone (ipfs.io|dweb.link|trustless-gateway.link).

I've filled this as a separate issue due to below caveat + this slack thread:

Important

Caveat: dweb.link is a subdomain gateway, so needs to have high cardinality Host values at *.ipfs.dweb.link and *.ipns.dweb.link merged with dweb.link.

How to represent it

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

These stacked diagrams are already dynamic, clicking on the legend will allow hiding ipfs.io and inspecting dweb.link or trustless-gateway.link alone: