Find and set up logging service

[jonrh]

Potential logging SaaS:

• https://rollbar.com/
• https://getsentry.com/
• https://logentries.com/
• https://raygun.com/
• https://newrelic.com/
• https://sematext.com/logsene/
• https://www.loggly.com/

Our requirements are to view errors and stack traces from a Python Flask app and ideally from our Swift iOS app.

• [x] Set up for our backend
• [x] Set up for iOS app
• [x] Set up for iOS evaluation app