Aggie should include an instance ID in error & exception logs

[karpawich]

When an error occurs or an exception is thrown from an Aggie instance, it logs that error or exception to a Slack channel and email address. However, if multiple instances were to be deployed at the same time, the team monitoring each would have no idea which instance the log came from.

A simple fix: I propose that we include an instanceId field in the config/secrets.json file that would prefix any logs sent to the active maintenance team.