Initial API
Setup testing architecture for API
Fix relations and metadata loading
Initial shipping method api tests
Rework code & fix issues after gathering feedback
Remove Alice and use already existing fixtures
Cleanup API code
Merge pull request #2061 from pjedrzejewski/feature/api

Rebased #1787 - Initial REST API
Refactor code to properly work with domain managers not repositories while creating resources
Extract interface from DomainManager class.
Fix some service declarations.
Fix more code to match manager & repository split
Implement transactions in DomainManager, remove useless code & cleanup