Switch to JAR-based deployment for Docker image

[vmax]

This pull request makes the following changes:

• compile and put JAR instead of Karaf module for Docker image

It relates to the following issue #s:

• Fixes Karaf-based Docker image fails to initialize #14

[cmanzur]

Thanks! This worked for me! Why is it not merged?

[bhamail]

Apologies for the slow reply. I don't think this is still and issue because I was able to use the following commands to build and launch the docker image:

1. mvn clean package
2. docker build -t nexus-repository-cargo .
3. docker run -d -p 8081:8081 --name nexus-repository-cargo nexus-repository-cargo
4. (wait for container to spin up, then): docker exec -it nexus-repository-cargo cat /nexus-data/admin.password && echo

Please post a new issue if the problem still exists.