Move all generated files during tests to maven target dir

Hi there,


By now when launching tests, some dir are created under `/data` or `/work` dirs.
IMHO, it's best to use `/target` dir to hold test dirs.

So, here a proposal for change:
- all tests creates data files under `/target/es/data` and work files under `/target/es/work`
- `src/test/resources/es-test.properties` is created and contain `path.data` and `path.work` settings
- `pom.xml` is modified to parse test resources and modify `${project.build.directory}` to maven target dir
- some TestNG tests are modified to use theses settings
- some *main()* tests (stress tests) are modified to use theses settings

HTH
David.