Make roundabout compatible with amended equivalence claims

[Gozala]

Context

Equivalence content claims will be adjusted to support blobs see

• https://github.com/w3s-project/content-claims/issues/60
• https://github.com/w3s-project/w3up/issues/1407

Task

Make roundabout capable of resolving pieces that correspond to blobs

[vasco-santos]

This should be done with https://github.com/w3s-project/w3infra/pull/359 merged, right @Gozala ?