[Feature Request] add layer-wise optimizers

### Feature request Context: https://github.com/huggingface/transformers/pull/29588#discussion_r1523510004 ### Motivation The layer-wise optimizers is not GaLore-specific. We could apply it to generic optimizers to save memory. For example, the 8bit Adam optimizer paired with the layer-wise optimization sounds like a pretty good option for me. ### Your contribution Have a try when it is supported