dependencies api: Persist lockfile parsing result to database

Created by: efritz

Add a new set of tables that mirror lsif_packages and lsif_references table. We need a new set of tables since the structure is different (the existing tables link uploads together, where we need to link repositories together directly).

We should construct a unified view that pulls the repository dependency information from the LSIF tables, then supplement it with lockfiles when missing. This should be what we query from as a first step, then fall back to writing through to this database layer on-demand.