[state_dict][3/N] Cleanup StateDictOptions, make it more readable (#111108)
1. Rename DistributedStateDictOptions to StateDictOptions.
2. Remove cpu_offload as we have not yet required this option.
3. Rename save_frozen_parameters to ignore_frozen_params.
Differential Revision: [D50209711](https://our.internmc.facebook.com/intern/diff/D50209711/)
Pull Request resolved: https://github.com/pytorch/pytorch/pull/111108
Approved by: https://github.com/wz337
ghstack dependencies: #111106, #111107
