PIM-1711 : add ProductRepositoryInterface to prepare Mongo impl
PIM-1771 : add FlexibleEntityRepositoryInterface
PIM-1771 : change visibility of getFlexibleQueryBuilder to protected
PIM-1711 : remove useless findAttributeByCode method
PIM-1711 : change visibility of findByWithAttributesQB to protected
PIM-1711 : remove useless findWithAttributes method
PIM-1771 : re-order methods
PIM-1711 : change visibility of getCodeToAttributes to protected, remove
it from FlexibleEntityRepositoryInterface
PIM-1771 : change visibility of applySorterByAttribute and begin to refactor the
implementation of FlexibleSorter
PIM-1771 : change visibility of applyFilterByAttribute to protected and begin to
refactor the implementation of FlexibleFilter
PIM-1771 : remove deprecated use statement
PIM-1771 : fix flexible filter
PIM-1771 : move FlexibleEntityRepositoryInterface from Doctrine to Model
PIM-1771 : move ProductRepositoryInterface from doctrine to model
PIM-1771 : add findOneByEntityAndCode in AttributeRepository and update
unit tests
PIM-1771 : rollback visibility of applyFilterByAttribute to continue the
grid bundle migration
PIM-1771 : rollback visibility of applySorterByAttribute to continue the grid bundle migration
PIM-1779 : update platform ref
Merge pull request #605 from akeneo/PIM-1771_product_repository

PIM-1771 product repository
PIM-1771 : fix CS