Unit test framework setup/exemplar

As an OpenLMIS developer, I want to write unit tests for my code and ensure they are included in normal UT execution and are included in any coverage stats (e.g. Sonar).

Acceptance:

• Implement unit testing frameworks in Architecture Overview's Tech Stack (https://openlmis.atlassian.net/wiki/x/IYAKAw), inform community on testing cases not covered by these tools (e.g. Spring Context's in PowerMock/Mockito)

• Tool framework reference included in the Indep. Service template and Service example, along with sample unit tests