Refactor Move atomic actions from benchmark scenarios

- Move atomic actions from benchmark/scenario/utils.py
to benchamrk/scenario/base.py
- Removed the scenario_utils imports
- Updated the scenario_base imports and related changes in
all rally files.

Closes-Bug:#1353464
Change-Id: I7f4d3e4b1d3650d97af08e5aca38fa80cc9f6fac
Merge "Refactor Move atomic actions from benchmark scenarios"