ARPA Exporter - Add python business-logic for building zipfile and emailing user

[as1729]

Ticket #3911 and #3909

Description

This PR ensures that:

1. The build-zip business logic adheres to the requirements of appending any new files based on the metadata CSV.
2. Sends an email to the user using USDR styling.

Screenshots / Demo Video

Testing

Automated and Unit Tests

• Added Unit tests

Manual tests for Reviewer

• Added steps to test feature/functionality manually

Checklist

• Provided ticket and description
• Provided screenshots/demo
• Provided testing information
• Provided adequate test coverage for all new code
• Added PR reviewers

[sophaskins]

Heya! This looks fine to me!

I do have one question, but it's not a review-blocker or anything. Where do the email_templates/base.html (and other templates) come from? I know that writing HTML emails that render acceptably in a wide variety of email clients/webmail sites can be tricky. If it's from some other example project/code, could we drop a comment or readme somewhere noting that?

Thanks!

[TylerHendrickson]

@sophaskins re

Heya! This looks fine to me!

I do have one question, but it's not a review-blocker or anything. Where do the email_templates/base.html (and other templates) come from? I know that writing HTML emails that render acceptably in a wide variety of email clients/webmail sites can be tricky. If it's from some other example project/code, could we drop a comment or readme somewhere noting that?

Thanks!

The base.html and formatted_body.html template files appear to be lifted from the usdigitalresponse/cpf-reporter repo (see here). However, those are adapted from the templates in this repository, packages/server/src/static/email_templates/base.html and packages/server/src/static/email_templates/_formatted_body.html, respectively. Notably, both base.html files are identical; formatted_body.html and _formatted_body.html have a very minimal difference on line 20 (the latter contains a text-transform: uppercase; styling directive that isn't present on the former.

Also worth noting: The server-side JS codebase in this repo provides a CLI helper utility for testing emails, provided by packages/server/src/scripts/sendDebugEmail.js, intended to be used in conjunction with the mailpit configuration present in our docker-compose.yml file. I have additional changes that add something similar to the arpa-exporter codebase, which I'll submit a PR for once this one is merged. I've used it locally to ensure that the email templates are rendering as expected for popular email clients.