Add 2020-2023 contribution data and import script

[hancush]

Overview

This PR adds a Makefile that downloads, compresses, and stores contribution and expenditure data, and a management command to import contribution data.

The management command takes 60-90 seconds locally, but 15-30 minutes on Heroku. As it will not be run frequently in a deployment environment, I feel trading off longer run time for the legibility of the ORM, rather than writing raw SQL, is more than worth it.

Notes

Some outstanding issues:

• Contribution and expenditure data do not link candidates to offices. This PR adjusts the display code to accommodate this missing piece of information, but we should consider adding it, using the Offices data available from NM SOS. (Example API call: https://login.cfis.sos.state.nm.us/api///Organization/GetOffices?jurisdiction=&jurisdictionType=&officeSought=&year=2023&district=&pageNumber=1&pageSize=1000&sortDir=asc&sortedBy=)
• There are some errors resulting from missing expenditure data, but I'm going to wait to handle them until I extend the new script to import expenditures.
• There are some weird edge cases to handle, e.g., the same candidate sometimes has a different OrgID across records, resulting in duplicates. We should figure out why this is and address it.

Testing Instructions

Tested extensively locally and against the review app.