Create ADTIFFWriter, make superclass for AD writers that the TIFF and HDF writers can extend.

[jwlodek]

Many of our beamlines use averaged TIFF files rather than HDF files for their data (particularly the diffraction ones). We should support both writers, and make a superclass so that other writers can be made in the same way if needed.

Acceptance Criteria

• Superclass that ADHDFWriter and ADTIFFWriter extend from
• ADTIFFWriter exists and can be used as a writer in an AD standard detector
• Mechanism exists for creating AD Standard Detectors with any subclass of ADWriter (with HDF being default).