Merge api-refactor branch into develop

[zpatrick]

Once https://github.com/quintilesims/layer0/issues/500 has been finished, we need to merge api-refactor into develop so we can get back into a sane branching workflow. This work item will be considered "done" once develop is in the state we all expect it to be in: that is all unit, smoke, and system tests are passing.

Keep PRs in Develop so we don't lose them during the replacement with api-refactor branch. PRs to watch:

• #600 Update contributing and release note links.
• #495 Update release notes and add script to update version

[sesh-kebab]

Changed "has been finished" to "is code complete" as 500 being finished would require documentation to be completed also.