Don't show logs in the failure reports by default

[christad92]

Adding the logs of a failed run (step) to a failure alert email potentially poses a security risk or a breach of data protection agreements as sensitive information might be logged during the run.

We should make it configurable such that users can toggle adding logs to the failure alerts via the project settings page.

@josephjclark suggested that we reference the actual error in the email but do not show all the logs. In this case, turning on the logs in failure alerts option will now let all users see logs in the email.

When Add logs to failure alerts is enabled, we should show a warning to users saying "Logs may include sensitive information".