docs: restructured docs layout

docs/user/api_reference/api_reference.md

@@ -0,0 +1,11 @@
+(user.api_reference)=
+# User API Reference
+
+```{eval-rst}
+.. autosummary::
+   :toctree: _autosummary
+   :template: custom-module-template.rst
+
+    bec_widgets.cli.client
+
+```