Add end-to-end test framework via playwright

[drewbo]

Changes proposed in this pull request:

• A new job, e2e-test, is added to the dev CI pipeline.
• This job creates a test user in the dev database, uses the associated token to run skeleton Playwright tests, removes the test user, then uploads the resulting test report to S3.

Notes

Possible improvements:

• Adding this to staging
• Making the test reports more discoverable

security considerations

CI creates (and removes) a test user with access to the dev database

[apburnes]

Awesome starting foundation!