We build iso image in two steps
1) We prepare cloud-init data using a krm function
krm-functions/cloud-init which uses arishipctl capabilities
to gather necessary data from the executor document bundle.
Cloud-init data files are written into a directory mounted
to the krm function container.
2) We build iso image using image-builder. While doing this
we mount the directory with cloud-init data files and set
necessary environment variables defined in the executor
document.
Relates-To: #440
Change-Id: Id0b34822e95f494d2e2f8fb407700b7f873e7c69