Add proper `QuantizationSpec` for `WeightOnlyPtq`.
Add proper `QuantizationSpec` for `WeightOnlyPtq`.

References to `*Preset` should be eliminated after `ExpandPresets`.
Apply proper `QuantizationSpec` changes to carry all information necessary for quantization passes.

Follow-up changes will include the following:
- Removal of `StaticRangePtqPreset` usage in quantization passes
- Removal of preset flag usages in pipeline and quantization passes
- Moving `stablehlo_op_quant_spec` to the beginning of the pipeline, so that individual op quantization spec information can be used to create proper `QuantizationMethod` per target quantizable block.
