PIM-3389 : use product media interface and not abstract class to type
hint
PIM-3389 : replace media manager unit test by specs
PIM-3389 : add spec for upload existing product media
PIM-3389 : complete media manager specs
PIM-3389 : add spec for duplicate method
PIM-3389 : re-order protected / public methods
PIM-3389 : remove useless media manager mock from astract form type unit test
PIM-3389 : replace unit test by specs for product file writer
PIM-3389 : move handle media methods from product manager to media
manager
PIM-3389 : move EE media manager method to CE
PIM-3389 : update media value setter and media manager
Merge pull request #1793 from akeneo/PIM-3389-media-manager

PIM-3389 : re-work media manager