Enable doc in Spanish (#16518)

* Reorganize doc for multilingual support

* Fix style

* Style

* Toc trees

* Adapt templates

docs/source/es/_config.py

+# docstyle-ignore
+INSTALL_CONTENT = """
+# Transformers installation
+! pip install transformers datasets
+# To install from source instead of the last release, comment the command above and uncomment the following one.
+# ! pip install git+https://github.com/huggingface/transformers.git
+"""
+
+notebook_first_cells = [{"type": "code", "content": INSTALL_CONTENT}]
+black_avoid_patterns = {
+    "{processor_class}": "FakeProcessorClass",
+    "{model_class}": "FakeModelClass",
+    "{object_class}": "FakeObjectClass",    
+}

docs/source/es/_toctree.yml

+- sections: 
+  - local: quicktour
+    title: Quick tour
+  - local: installation
+    title: Instalación
+  title: Get started
+- sections:
+  - local: pipeline_tutorial
+    title: Pipelines para inferencia
+  - local: training
+    title: Fine-tuning a un modelo pre-entrenado
+  - local: accelerate
+    title: Entrenamiento distribuido con 🤗 Accelerate
+  title: Tutorials
+- sections:
+  - local: multilingual
+    title: Modelos multilingües para inferencia
\ No newline at end of file

docs/source_es/installation.mdx → docs/source/es/installation.mdx

@@ -236,9 +236,3 @@ Una vez que el archivo se descargue y se almacene en caché localmente, especifi
 Para más detalles sobre cómo descargar archivos almacenados en el Hub consulta la sección [How to download files from the Hub](https://huggingface.co/docs/hub/how-to-downstream).
 
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