Improve test.sh ...

Don't move the original initializers directory, but rather use the one
with the modified initializers in it.

Ignore local override file ...

Adding an ignore rule for docker-compose.override.yml should allow people to clone this repo and use an override file to match their environment, without that file causing issues every time they pull a new version of the repo.

externalize netbox download with wget

❇️ Make the default configuration cluster ready ...

This changes the default configuration to be better prepared for
usage with container management platforms, such as Docker Swarm,
Kubernetes or OpenShift.

Closes #27.