Add a regression test for non-inlined dnslinks on localhost tests

[laurentsenta]

Extracting this issue out of #8

At the moment, we configure Kubo's gateway with inlining on both localhost and subdomains gateways:

gateway-conformance/kubo-config.example.sh

Line 13 in 8ee866c

"InlineDNSLink": true,

This test might mean running the conformance test suite twice, once against an inlining gateway and once (with different specs) against a gateway running a different configuration.

• Is this test still relevant?
• Can we work around having to run the gateway twice?
• worst case scenario
  • create a new spec for inlining
  • create a new test suite without inlining (the current test should be a good starting point)