Start a shared library for Services

In order to avoid being redundant in our services, we will eventually want to have some kind of a "shared library". This story captures determining what this shared library is and how it is implemented. The spike should include how to add the shared library in the build process of the independent service.

OpenLMIS services could benefit from a shared library that reduces copy/pasted code between Independent Services. This shared library will contain only Java classes. The shared library should be published to Maven and pulled in to services from there.

A concern with a shared library is what occurs when the library has dependencies on 3rd party libraries that a Service also would have - and what happens when the versions are different on the classpath. To that end we want to publish guidance that takes a conservative approach:

• be careful about dependent libraries that may also be used in the services

• no spring dependencies

Acceptance:

• a new git repo exists: openlmis-service-util

• the utility project builds to a JAR via Gradle

• the JAR is published to Maven central repo (OSSRH) in the same manner as the extension point & module mechanism (a Jenkins job will be needed)

• the JAR is versioned similarly

• the README has the stringent guidance for which utilities may be included