[docs] Romanian translation of `contributing.md`, `modular_transformers.md`, `multimodal_processing.md`, `add_vision_processing_components.md`, `add_audio_processing_components.md`, `modeling_rules.md`, `model_output_tracing.md`, `auto_docstring.md`, `testing.md`, `pr_checks.md` and `add_new_model.md` . (#46345)