Defaults to disabled. Included in onboarding.

Closes #303 

* Reset version to 0.0.0-semantic-release
* Add semantic-release and condition-circle
* Add circleci deployment config

* Move yarn and npm helpers into branch worker

* Fix name

* Move package-json helper

* Update name

* Move changelog

* Move github-app

* Remove unused platform

* Move logger

* Fix lint

Closes #375 

* Detect versions at startup

* Add meaningful error messages when problems with npm or yarn

* Test helpers

* Test global versions

* Skip repositories with no package.json

Closes #376

* Fix await

* Refactor file file check

* Update tests

Fixes #371

* Add debug messages to API

* Fix rebase logic

* Fix tests

* Simplify logic

* Update branch.spec.js

Closes #333

* Update dependency prettier to version 1.5.2

* lint fix

* Store repoIsOnboarded in config

* Use package file renovate config for onboarding

Closes #368

* Add branchName to mergeRenovateJson

* Split onboarding into branch and PR

* Update onboarding description

* remove snapshot

* Update tests

* Update onboarding text