image building: make logs / output more accessible and usable

[redhat-openstack]

image building: make logs / output more accessible and usable

[halcyondude]

Update, as it's been a while.

• https://review.gerrithub.io/#/c/276629/ addresses part of this, as we're now capturing log files from the various steps of the build process, bundling them, and co-locating with the images produced.
• When https://review.gerrithub.io/#/c/277420/ lands the logs + images are copied out (if enabled).
• since this issue was logged, we're now using tripleo-common to wrap DIB, and the output (which was the most verbose) is now captured to a file. It's still not an awesome experience but it's no longer thousands of lines --> stdout --> ansible task output.
• have been exploring wiring in ARA
• CI jobs have been using collect-logs. Considering moving logs --> /var/log (or another standard location) so it just picks them up, instead of needing to have collect-logs go searching for them in artib_working_dir. It sounds like a minor/subtle point, but the way we're dealing with logging in RDO and downstream CI it's necessary.

[halcyondude]

Most of this is accomplished. ara can be brought in as a separate role, or as something this role exports configuration for via pip mechanism. Either way it's a new/different issue. Closing.