Add LoRA dropout

[rockerBOO]

LoRA Dropout as a Sparsity Regularizer for Overfitting Control
https://arxiv.org/abs/2404.09610

Header	Header

Note: only currently implemented for Flux

network_args = [
    "lora_dropout=0.5"
]

--network_args lora_dropout=0.5

[67372a]

@rockerBOO for awareness, for reasons not clear, the authors have retracted / withdrawn their publication as per https://openreview.net/forum?id=c4498OydLP. Reading through some of the reviews, it seems like the authors made flawed assumptions and significant errors.

[rockerBOO]

@67372a Thank you. I'll have to think about what that might mean for this PR. For now it'll probably just remain up in the draft state.