file.data -> file.snapshot

[samuelstroschein]

Context

Easy win to let a file point to a snapshot.

• faster queries because the blob is outside of the file table
• less disk space usage LIXDK-194

Proposal

Remove file.data in favor of file.snapshot_id

[samuelstroschein]

Using the snapshot table is not ideal.

• the snapshot_ids constantly need to be updated on the file table
• contradicts LIXDK-219

I am closing this issue as a distraction until for the public preview on dec 16