Remove DBR quantization from the codebase (#83642)
Summary:
DBR quantization is a no-go for now because it does not align well with
PyTorch 2.0 plans and we do not want to build yet another tracing system.
Deleting it from the codebase for now since there are no plans to develop
this in the near future. We can bring it back at a later time if necessary.
Test plan:
CI
Differential Revision: [D38839556](https://our.internmc.facebook.com/intern/diff/D38839556)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/83642
Approved by: https://github.com/andrewor14, https://github.com/jerryzh168
