Add e2e testing guide

[cquinn540]

Contributor checklist

• This pull request is on a separate branch and not the main branch
• I have run the tests for the backend and frontend depending on what's needed for my changes as described in the testing section of the contributing guide

---

Description

This adds a guide for writing e2e tests to our documentation. The focus is on the patterns we are using and why.

Related issue

• Create a guide for writing and running e2e tests #1049

[netlify]

✅ Deploy Preview for activist-org canceled.

Name	Link
🔨 Latest commit	ed4a16c
🔍 Latest deploy log	https://app.netlify.com/sites/activist-org/deploys/67abd2fae2347d00084f6115

[github-actions]

Thank you for the pull request! ❤️

The activist team will do our best to address your contribution as soon as we can. If you're not already a member of our public Matrix community, please consider joining! We'd suggest using Element as your Matrix client, and definitely join the General and Development rooms once you're in. Also consider attending our bi-weekly Saturday developer syncs! It'd be great to meet you 😊

[github-actions]

Maintainer Checklist

The following is a checklist for maintainers to make sure this process goes as well as possible. Feel free to address the points below yourself in further commits if you realize that actions are needed :)

• The TypeScript and formatting workflows within the PR checks do not indicate new errors in the files changed

• The Playwright end to end and Zap penetration tests have been ran and are passing (if necessary)

• The changelog has been updated with a description of the changes for the upcoming release and the corresponding issue (if necessary)

[andrewtavis]

Thanks for the documentation here, @cquinn540! Happy to have this finalized :) I did some minor edits, with the most significant being removing periods from unordered lists. Till now we haven't been using them, and I figure it's best to be consistent.