Lumina lora updates

[rockerBOO]

Update lora_lumina with the following:

• embedder_dims instead of in_dims
• caption_extension allow for more flexibility. For instance it would add a . if it wasn't the first character. Now can support suffixes to captions. Use case is where I have _combined.txt for the caption extension. Added a loop to check if the caption file is found or tries with a . to the extension.
• Add FinalLayer to main module to train. I feel it is an important module to train but could revert and put back in "embedder_dim"
• Add train_block_indices but might need some more testing.
• Refactored some of the code to remove some nesting.

If you have any feedback I can adjust anything. I kept changing things but maybe they were not a good idea.

Thanks!

[sdbds]

It is considered that the captions suffix can be directly handled using pathlib.
After that, I will modify that part.