SD-302: Add user: test backend, create unit tests, review
SD-302: Add user: test backend, create unit tests, review

Updated behave tests and steps, moved status check to
"Then" sentences
fix(heroku): remove SERVER_NAME setting
fix(etag): disable etags handling

SD-293
fix(heroku): update eve-elastic version to make use of source param
fix(auth): make auth error responses json

SD-312