Documentation: Howto debug ignited behavior

[bbros-dev]

Document howto debug ignited behavior in a running system, e.g. when launched by a service manager:

• Default log location(s)
• What to look for when things are good
• What to look for when things are bad, CNI, runtime, etc. etc.

[bbros-dev]

Closing. Following a review, we will not be using ignite outside of developer personal workflows, so won't be able to devote any time to issues outside of that scope.