More useful errors, by exit code

[wyhaines]

Is your proposal related to a problem?

There are conditions that can cause ambiguous errors like:

service "contracts-topos" didn't complete successfully: exit 137

This is difficult to take proactive action on. This error, for instance, indicates that the VM ran out of RAM.

Describe the solution you'd like

Add specific feedback if an error occurs with an exit code that is meaningful and actionable.

Describe alternatives you've considered

A simpler alternative is to document this error in the README. The drawback to that is that, eventually, the README's troubleshooting section may become quite large, so perhaps it would be beneficial for the troubleshooting feedback to be given directly within the tool?