Add Idefics3 module and image processing functionality

- Introduced a new module `idefics3` in the models directory, which includes a new `processing.rs` file.
- Implemented the `Idefics3ImageProcessor` struct with methods for image resizing, splitting, rescaling, and normalization.
- Updated the main models module to include the new `idefics3` module alongside existing modules.
- Enhanced image processing capabilities to support various preprocessing tasks for vision models.

Author: akshayballal95

rust/src/models/idefics3/mod.rs

@@ -0,0 +1 @@
+pub mod processing;