Wide merkle query

[fabrizio-m]

Explain your changes: Adding support for wide merkle queries that request more than 2 nodes during sync.

Explain how you tested your changes: Ran V2 node, for this V1 -> V2 case I started the V2, got it to connect to devnet, and then started the V1 with the running V2 as only peer.

Checklist:

• [ ] Dependency versions are unchanged
  • Notify Velocity team if dependencies must change in CI
• [ ] Modified the current draft of release notes with details on what is completed or incomplete within this project
• [ ] Document code purpose, how to use it
  • Mention expected invariants, implicit constraints
• [ ] Tests were added for the new behavior
  • Document test purpose, significance of failures
  • Test names should reflect their purpose
• [ ] All tests pass (CI will check this if you didn't)
• [ ] Serialized types are in stable-versioned modules
• [ ] Does this close issues? List them