Added Optimizer configuration that supports optimizer type, learning rate, momentum, and weight decay configurations.

[SSYernar]

Summary: This commit introduces enhancements to the optimizer configuration in TorchRec. It now supports specifying the optimizer type, learning rate, momentum, and weight decay. These changes provide more flexibility and control over the training process, allowing users to fine-tune their models with different optimization strategies and hyperparameters.

Differential Revision: D76559261