[ao] Added fx model report per_channel detector

Summary: This code is meant to be a tool to help people get the most out
of their backend by hinting them to use per_channel quantization if it's
supported, which will help increase accuracy significantly. The code is
completed and ready to be reviewed.

Test Plan: test/quantization/fx/test_model_report_fx.py

Reviewers:

Subscribers:

Tasks:

Tags:

Pull Request resolved: pytorch#79104

Approved by: https://github.com/HDCharles

Author: vspenubarthi