update correction plugin device server to have same API to set/get file
RoiCounters, Mask, FlatField Rois2Spectrum and now RoiCollection have to many differences with API. Some refactoring is necessary to provide the same API to set/get file with both command and attributes. In Addition a new command setFile has been added to all plugin and the setImage kept for backward compatibility. A new command should be also added to allow to upload directly an image, for instance uploadImage() with Tango type to be defined.