Console error reporting service

[tjkirch]

If the system can't start required services, it would be helpful to output more error messages to the console for debugging. (The console performance impact no longer matters if the system isn't usable.)

We currently only output ERROR-level output from first-party services, but it could be useful to see the last 10 lines of journalctl output from all failed services, for example.

@jamieand has experience from #86 on how we could detect a failed state; see that for background. After detection, perhaps just iterate through failed services and tail their logs, to start?