[quant][core][better-engineering] Rename files in quantized/cuda directory to conform with non-quantized countertpart filenames #77431
Summary:
Names of analogous files in quantized directory (previously snake case) were inconsistent with
their non-quantized filename counterparts (pascal case). This is the fourth of a series of PRs that changes
all files in quantized (and sub-directories) dir to have pascal case.
Some files have not been renamed as it is causing issues related to
custom class with import torch at runtime.
Test Plan:
```
python test/test_quantization.py
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/77436
Approved by: https://github.com/jerryzh168
