setting up a test env based in local development in this repo

The changes proposed in this MR will enable developer to use a test environment from within the repo. this means that a xar package will be created and passed to a compatible exist-db that will be downloaded and installed at the test directory. This requires some changes in the ant build. Due to these changes, the gitlab ci is able to test the installation and to run all specified tests. (may be this needs additional setup.)