PIM-2911 : refactor product controller
PIM-2911 : extract locales and channels preparation in dedicated methods
PIM-2911 : add a Rest Product Handler
PIM-2911 : add a access denied case
PIM-2911 : add some spec for the product handler
PIM-2911 : introduce a dedicated webservice serializer
PIM-2911 : re-organize the normalizers to avoid conflicts with
SerializerAwareInterface by defining the normalizers as service for each serializer
Merge branch 'master' into PIM-2911

Conflicts:
	CHANGELOG.md
Merge pull request #1363 from akeneo/PIM-2911

PIM-2911 :  refactor get product api controller / re-organize serializers