We need to increase the size of the esp image for downstream
compatibility.

Sensor data collection was intended for an earlier use of
the ironic-image and resulting ironic container image in order
to supply data to prometheus about hardware that has not yet
been deployed upon. Since the deicsion was made not to leverage
the data, it seems pointless to collect sensor data.

As such, disable sensor data collection.

An improvement for testing and customization, moving all the
files we need to install in the main image to a file and having
dnf read its content.
This allows exotic compositions of sources, like urls and local dirs,
without having to touch the Dockerfile.

This will allow to pass a custom list of packages to install during
build time with very little effort.