[quant]ao migration for quantization mappings and fuser method mappings hg mv (#64985)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64985
moving quantization_mappings.py and fuser_method_mappings.py to the ao folder while retaining backwards compatibility
also added dict test
ghstack-source-id: 138215312
Test Plan:
buck test mode/dev //caffe2/test:quantization
https://www.internalfb.com/intern/testinfra/testrun/7036874471986444
buck test mode/dev //caffe2/test:quantization -- TestAOMigrationQuantization
https://www.internalfb.com/intern/testinfra/testrun/5348024625792701
Reviewed By: z-a-f
Differential Revision: D30982551
fbshipit-source-id: 00f53bd44009d6012a7de852000aad6885131edb
