[quant] ao migration of observer and qconfig (#64982)
Summary:
(Had to recreate this diff so it wasn't dependent on the stack)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/64982
migration of qconfig.py and observer.py to torch/ao/quantization using new test format
ghstack-source-id: 138215256
Test Plan:
buck test mode/opt //caffe2/test:quantization
https://www.internalfb.com/intern/testinfra/testconsole/testrun/8444249354294701/
buck test mode/dev //caffe2/test:quantization -- TestAOMigrationQuantization
https://www.internalfb.com/intern/testinfra/testrun/3940649742829796
Reviewed By: z-a-f
Differential Revision: D30982534
fbshipit-source-id: 48d08969b1984311ceb036eac0877c811cd6add9
