preparetion for real cluster tests

  1. Elliptics logs and configs paths were changed.
    They are located in **elliptics_dir** directory. It will simplify working with elliptics logs and configs.

  2. collecting logs playbook was updated:
    * `fetch` module usage was fixed
    (after fetching logs we were trying to iterate through files (to zip them) when there were only directories)
    * logs directories were parameterized
    (we can change them in one place now)

  3. elliptics config was extended with new parameters

  4. unnecessary files were removed

reviewers: @uvizhe