Changes

Speed up the container build

Assuming the locally built artifacts changes more
frequent than the package dependencies, it makes more sense
to add the local artifacts as a last step to the container.

This will more often use cached build steps, and thus
speed up the container build process and, as image layers
can be re-use, requires less bytes to be transmitted when
pushing.

Signed-off-by: Jens Reimann <jreimann@redhat.com>

Improve the container build script

This change makes the build script more flexible:

* Allow to run from outside the script's directory
* Allow to override most of the parameters
* Allow to change the container registry
* Allow to override the version

Signed-off-by: Jens Reimann <jreimann@redhat.com>