Implement transform function for asset data

[Isaiah-Turner]

What

We need to implement a function that transforms the information we get about assets from the new ingestion system into a form suitable for BigQuery. Part of #33.

Why

This function will be used when exporting asset information from the CLI.

[Isaiah-Turner]

We no longer need this. We cannot recreate the ids in the history_assets table. There's no need for a transform function since we won't have that table anymore.