* Added new JavaScript evaluator py_mini_racer. Advantages:
* is distributed as wheel package
* supports differences platforms
* live project
* BUILD_V8EVAL was removed because it was replaced by py_mini_racer in
Mistral Docker image
* Added stevedore integration to javascript evaluators
* Refreshed javascript tests. Add test for py_mini_racer evaluator
* Install py_mini_racer library in during mistral test
* Refreshed javascript action doc
Change-Id: Id9d558b9b8374a2c2639e10cb1868f4e67f96e86
Implements: blueprint mistral-add-py-mini-racer-javascript-evaluator
Signed-off-by: Vitalii Solodilov <mcdkr@yandex.ru>