Tests are collecting artifacts now and some small changes:

* multiple times used expressions were replaced with parameters
(expressions like path to log file were used several times and with added
parameters we can change them in one place, instead of changing them in every
place)
* **logging_level** option was removed
(this option was never used - all tests want to collect maximum detailed logs)
Test runner was updated:

It doesn't collect artifacts (all artifacts should be collected by tests) and
just uploading it to file storage.
Collecting recovery logs was added and small fix:

* recovery dc and merge logs are collecting now too
* template for configuration file (v2.25) was corrected
* all truly teardown steps were moved to teardown script
Merge pull request #71 from kis8ya/features/artifacts-collecting

Tests are collecting artifacts now.