Add the capability to create a jar with dependency

Summary: Useful to make standalone scrips and executables. This won't generate a jar-with-dependency with the mvn package phase.

Test Plan: mvn assembly:assembly generates jar-with-dependency file under target

Reviewers: jd

Reviewed By: jd

Subscribers: eng

Differential Revision: http://phabricator.scale-data.com/D1134