📝 Add BO, COM and ENUM to the sidebar (#696)

* 📝 Add BO, COM and ENUM to the sidebar

* 🇩🇪 translate to german

* 🎨 change order

* 🔥 Remove Module Reference

* 🎨 Put licence at the end

* Translate to english terms

* Pre-commit trim trailing whitespace

---------

Co-authored-by: Annika Schloegl <annika.schloegl@hochfrequenz.de>

Author: hf-krechan

docs/index.rst

@@ -31,15 +31,17 @@ Contents
    :maxdepth: 2
 
    Fundamentals <fundamentals>
-   Data Model <api/modules>
+   Data Model Overview <api/modules>
+   BusinessObjects <api/bo4e.bo>
+   Components <api/bo4e.com>
+   Enumerations <api/bo4e.enum>
    Versioning <versioning>
    Release Workflow <release_workflow>
    Contributing <contributing_guide>
    Changelog <changelog>
    Authors <authors>
    License <license>
 
-
 Indices and tables
 ==================