Distinguish overlapping class names in the signal_processor module

[mgiammar]

Some of the operations available throughout the signal processor module have duplicate names but different inheritance patterns/uses. For example:

• mrsimulator.signal_processor.Scale inherits from class Operation and scales all dependent variable values in a CSDM object by a constant.
• mrsimulator.signal_processor.affine.Scale inherits from class AffineTransformation and scales the coordinates of a CSDM dimension by a constant.

These two classes perform distinct and useful functions, but share the same name which will cause confusion. Class names, descriptions, and documentation should be updated to remove any ambiguity before version 0.8 is released.

Additionally, the ComplexConjugate class should be implemented for convenience sake.

[mgiammar]

Should not be confusion between the sp.Scale and sp.affine.Scale operations. Additionally, the ComplexConjugate operation can be done natively with csdmpy.