Refactor worker code (#362)

* Move package-file worker

* rename to renovatePackageFile

* Move packageJson

* Add getDepTypeConfig

* Add

* Revert "Add"

This reverts commit d034e6149af90caf57de3f1b5069674fd8537bd3.

* Refactor versions

* rename findPackageFileUpgrades

* rename versions

* packageWorker

* Refactor promises

* move snapshots

* Rename

* Refactor versions

* Refactor

* Finish package worker

* Major refactor

* Remove worker tests

* package/versions

* Finish packageWorker tests

* package-json test

* Finish dep-type tests

* Add back package-json helper test

* Refactor package-file

* Add back branch and pr

* Add back remaining worker tests

* update tests

* remove snapshot

* Fix dep-type coverage

* Remove old tests

* Coverage