Write methods to populate DeepDAO data

[notchia]

Use the DeepDAO API to populate the governance address info and some contextual information.

The data model for the DAOs, addresses, and categories/platforms for context has been created. We need to transform the responses returned by API request into records that can be saved to the database. This is probably best done with a handler class that has some methods for extracting, transforming, and loading the data. See the comments in the data model for what fields in the API responses could go where.