As part of the longer piece of work to introduce a suite of tools for
managing dependency-management-data, we're starting with the commands to
bootstrap a DMD SQLite database.

This mirrors the `filter.rb` from renovate-graph with some additional
data points we've found useful at Deliveroo.

We use sqlc to make it nicer to interact with our database in a strongly
typed fashion.

As it doesn't support migrations - and we're not yet at the point we need
migrations - we can simply just run the `CREATE ...` steps.

Closes #2