[ao][sparsity] Base scheduler class for Data Schedulers (#79817)
The BaseDataScheduler is the abstract scheduler class specifically for the
BaseDataSparsifier class. This class controls a specific hyperparameter of
the sparsifier class and varies it across the training process (or across time).
Args:
data_sparsifier (instance of BaseDataSparsifier)
Implemented class data sparsifier class wherein the update_mask is implemented
schedule_param (str)
A specific hyperparameter of the passed sparsifier that needs to be scheduled/varied
last_epoch (int, default=-1)
This is specifically is passed when training needs to be resumed from a particular
point.
verbose (bool, default=False)
Verbosity of the BaseDataScheduler
The *get_schedule_param()* function needs to be implemented by the user.
Test Plan:
```python test/test_ao_sparsity.py TestBaseDataScheduler```
Differential Revision: [D37358608](https://our.internmc.facebook.com/intern/diff/D37358608)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/79817
Approved by: https://github.com/jerryzh168, https://github.com/z-a-f
