This patch completely removes the compile-time dependency on core for both test and main sources by introducing two new modules.
1) `test-common` include all the common test implementation code (including dependency on :core for BrokerServer, ControllerServer, etc)
2) `test-common:api` new sub-module that just includes interfaces including our junit extension
Reviewers: David Arthur <mumrah@gmail.com>
Chia-Ping Tsai