Minor change on api
Prototype of new localization aware object mapper in the api
Fix bugs and improve object mapping in api
Rename api projects
Unit tests for DefaultObjectMapper
Customize product and variant mappers in api, and refactor apis
Refactor front api to make it real switchable

- Because of the way we register the api instances, the original implementation is actually not switchable, so now we only register the entry api to make it switchable
- Add ApiContext so each api can access the site information easily
Rename API to Api to follow the convention made by .net framework