EZP-22781: Added an IOServiceInterface
EZP-22781: Added an ImageStorage Legacy IOService
EZP-22781: Refactored File FieldTypes SPI tests

Now takes configuration from the test container (service.ini).
Should now delete its files after testing.
EZP-22781: Fixed review remarks
Merge pull request #828 from ezsystems/EZP-22781-preview_image_draft

Fixed exception when loading images with 'images-versioned' path