Add data columns by root sync request

[dapplion]

Issue Addressed

Part of

• DAS - Tracking Issue #4983
• Progressively merge das to unstable #6072

Proposed Changes

Add support inside sync network context to issue, track and complete data_columns_by_root requests.

This type of request will be issued by a higher order custody by root request. In summary:

• Block lookup will trigger a custody by root request, code here: Add sync lookup custody request state #6257
• Custody by root request will trigger data columns by root request(s): TODO
• Data columns by root request complete: this PR

The handler of data_columns_by_root requests is quasi-identical to blobs_by_root request handler. Same verify conditions and completeness conditions.

[dapplion]

Closing for equal PR but from sigp repo

• Add data columns by root sync request #6274