feat: post-deployment GHA playwright checks

[megahirt]

Through some conversations in the office, @hahn-kev and I have decided that it would be good to create some simple playwright scripts that exercise our website in some basic ways:

• is the site up and running after a deployment?
• is OAuth functional? (simple click-through)
• can you login via the username/password path?

The purpose of the post-deployment playwright checks is to ensure that a deployment is successful and that some of our most critical paths are not broken. Currently, we have no other way besides post-deployment developer testing in QA and production or through user bug reports to know if a service or critical path is broken.

These checks would be encapsulated in a separate playwright environment and run in a separate GitHub action.

The GitHub action check would be triggered:

• on a cronjob run once daily
• triggered on workflow_call from the deployment action as a dependent step
  - if the check failed, it would fail the whole deployment step
  - The check step would need to have a time delay built in, e.g. 1 minute, to allow time for the deployment to take place