Add save and load utils function to documentation

Author: jaime-cespedes-sisniega

docs/source/api_reference/utils.md

@@ -8,5 +8,6 @@ The {mod}`frouros.utils` module contains auxiliary classes, functions or excepti
 utils/checks
 utils/data_structures
 utils/kernels
+utils/persistence
 utils/stats
 ```

docs/source/api_reference/utils/persistence.md

@@ -0,0 +1,9 @@
+# Persistence
+
+The {mod}`frouros.utils.persistence` module contains auxiliary functions to persistence objects.
+
+```{eval-rst}
+.. automodule:: frouros.utils.persistence
+    :members:
+    :no-inherited-members:
+```

docs/source/examples.md

@@ -5,4 +5,5 @@
 
 examples/concept_drift
 examples/data_drift
+examples/utils
 ```

docs/source/examples/utils.md

@@ -0,0 +1,7 @@
+# Utils
+
+```{toctree}
+:maxdepth: 1
+
+utils/save_load
+```

docs/source/faq.md

@@ -83,3 +83,10 @@ including guidelines for reporting issues, submitting feature requests, and cont
 
 Frouros does not currently provide built-in visualization tools for drift detection results, but it is planned to 
 include them in future releases.
+
+## How can I persist a detector or callback for later use?
+
+Frouros provides a [persistence module](./api_reference/utils/persistence.html) that allows you to persist a detector 
+or callback for later use. It offers [save](api_reference/utils/persistence.html#frouros.utils.persistence.save) and 
+[load](api_reference/utils/persistence.html#frouros.utils.persistence.load) methods to save and load the detector or 
+callback to and from disk, respectively.