GET CAR with dag-scope=block of UnixFS file on a path (format=car)

Implementation	bifrost-gateway	boxo	kubo
Conformance Version	main	main	main
Total	✅14	✅14	✅14
Body	✅2	✅2	✅2
Header Accept-Ranges	✅2	✅2	✅2
Header Content-Disposition	✅2	✅2	✅2
Header Content-Type	✅2	✅2	✅2
Header Etag	✅2	✅2	✅2
Header X-Content-Type-Options	✅2	✅2	✅2
Status code	✅2	✅2	✅2