Add a reference to the REST API

Author: FrancescAlted

doc/Caterva2.rst

@@ -56,7 +56,14 @@ On demand access to remote Blosc2 data repositories.
       :color: dark
       :click-parent:
 
-      To the API reference
+      To the Python API reference
+
+    .. button-ref:: reference/rest_api
+      :expand:
+      :color: dark
+      :click-parent:
+
+      To the REST API reference
 
   .. grid-item-card::
     :img-top: _static/index_contribute.svg
@@ -83,7 +90,8 @@ On demand access to remote Blosc2 data repositories.
 
     Getting Started <getting_started/index>
     Tutorials <tutorials/index>
-    API Reference <reference/index>
+    Python API Reference <reference/index>
+    REST API Reference <reference/rest_api>
     Utilities <utilities/index>
     Development <development/index>
     Release Notes <release_notes/index>

doc/reference/index.rst

@@ -9,4 +9,3 @@ API Reference
     file_class
     dataset_class
     utils
-..    subscriber_class  # TODO: how to document the REST API?

doc/reference/rest_api.rst

@@ -0,0 +1,11 @@
+REST API Reference
+==================
+
+.. toctree::
+    :maxdepth: 1
+
+A REST API is provided by the Caterva2 server. It is a simple HTTP API that allows you to interact with the Caterva2 server using standard HTTP methods. The API is designed to be easy to use and understand, and it provides a simple way to access the functionality of the Caterva2 server from any programming language that can make HTTP requests.
+
+The most updated version of the REST API is available at https://cat2.cloud/demo/docs.
+
+It is important to note that the REST API is not intended to be used as a replacement for the :doc:`Caterva2 Python client API <index>`. The Python client API provides a more convenient and efficient way to interact with the Caterva2 server, and it is recommended for most use cases. However, the REST API can be useful in certain situations, such as when you need to access the Caterva2 server from a programming language that does not have a Caterva2 client library, or when you need to integrate Caterva2 with other systems that use HTTP.