Remove unnecessary state dict and load_state_dict functions

[eracah]

What does this PR do?

The following items don't need to implement state dict and load_state_dict functions:

1. DeviceGPU
   • returns cuda rng state. This isn't used anywhere since we just use rng state in the reproducibility module
2. All the other devices
   • just return {} for state_dict and error for load_state_dict. Do we even need to have these functions implemented?
3. Loggers
   • just wandb and progress_bar, which are never actually used in practice.

[mvpatel2000]

LGTM

[bigning]

thanks for cleanup!