Add Utils for federated learning scenarios (#13014)
**Description**: utils for federated learning.
**Motivation and Context**
- This PR includes utils that will be used on federated learning
scenarios.
- Exposing python bindings to some utils, and added a util to calculate
the difference between two buffers.
Co-authored-by: Adam Louly <adamlouly@microsoft.com@orttrainingdev7.d32nl1ml4oruzj4qz3bqlggovf.px.internal.cloudapp.net>
Co-authored-by: Baiju Meswani <bmeswani@microsoft.com>
