onnxruntime

00c3cd49 - [QDQ Quantization] Refactor shared functionality into a base quantizer (#19817)

[QDQ Quantization] Refactor shared functionality into a base quantizer (#19817) ### Description This PR does not add or remove any functionality. It refactors common functionality shared by the `ONNXQuantizer` and `QDQQuantizer` classes into a new `BaseQuantizer` class. This change helps decouple the QDQ quantizer from other quantization modes and makes it easier to determine if a change to one quantization mode will impact another. ### Motivation and Context An upcoming PR aims to add mixed-precision support to QDQ models (e.g., one part of the graph uses u8 activations and another uses u16 activations). This change makes the upcoming PR smaller and should presumably make determining the impact on existing features more straightforward.