Migration for new Findings links data

Why are we doing this work

After introduction of new Finding Links model and tables in #239174+, we need to migrate the data from raw_metadata to the new table.

Use !49762 (closed) as a baseline for this change.

Relevant links

See Design Issue for details.

Non-functional requirements

N/A

Implementation Plan

• database Implement background migration to populate data for previously introduced links columns & tables

Verification steps