Error and Exception Tracking

[mikelnorth]

As a site maintainer I want to be notified of any production errors that happen.

Acceptance Criteria:
Maintainers are alerted of production errors

Technical Details
Sentry could be a good option for this as their free tier integrates with slack and we can create a channel for site alerts. We don't have to do this solution and can do whatever the engineer finds best. If we use a solution other then sentry and slack we should discuss with maintainers to make sure everyone agrees to the solution.