[Feature] Sync log for deployments

[Data-Nexus]

Description

We have a created_at field in the deployment_schemas table, but it would be nice to also have a synced_at.

This is primarily to benchmark sync speeds for various subgraphs.

Are you aware of any blockers that must be resolved before implementing this feature? If so, which? Link to any relevant GitHub issues.

No response

Some information to help us out

• [X] Tick this box if you plan on implementing this feature yourself.
• [X] I have searched the issue tracker to make sure this issue is not a duplicate.