[QuantizationModifier] refactor base - move deprecated code to legacy file, add object routing for yaml load

[bfineran]

first PR for QuantizationModifier refactor. moves the existing modifier and tests into a "legacy" file. Creates a template object for the new modifier. To maintain backwards compatibility, we add support for detecting which object should be loaded for a yaml QuantizationModifier at load time by adding an extra pass to the constructor. For now this is done by detecting the submodules field in the legacy modifier which is included in all deployed recipes.

test_plan unit test included for yaml dispatch. legacy quantization modifier tests updated and pass

[github-actions[bot]]

@anmarques @rahul-tuli assigned for review