Add dedicated compliance targets for Trustless Gateway

[lidel]

Discussed this briefly with @laurentsenta, projects like Saturn, Rhea, Boost etc will benefit from a test targets that only check compliance with https://specs.ipfs.tech/http-gateways/trustless-gateway/ spec.

We already have some prior art for Subdomain Gateways and IPNS.

Ideally, we would provide targets for requested subsets of the spec (we know some use cases won't care about IPNS or CARs).

My thinking is to add:

1. trustless-block-gateway Just Blocks (no paths) – bare minimum, the most basic type of trustless gateway
2. trustless-block-car-gateway Blocks and CARs with paths (@aarshkshah1992 would like to run this in Rhea projects)
3. trustless-block-car-ipns-gateway Blocks, CARs, and IPNS Records, enabling end-to-end verifiability of both /ipfs and /ipns. (we would run this in Kubo and bifrost-gateway)

cc @hacdias – up to you if we add this to #56 or do a follow-up PR

[hacdias]

I think we should do this after #56. Some of this might require #73 for Etag and If-None-Match compliance.