Refactor Sphinx documentation for better structure.

This change improves the layout of the Read the Docs documentation by creating a dedicated API reference page.

Key changes:
- Created a new `docs/api.rst` file to contain all C++ API documentation generated from Doxygen.
- Added references to both `MedicalLib/MedicalLib.h` and `MedicalLib/Patient.h` in `api.rst`.
- Updated `docs/index.rst` to remove the inline API documentation and include a link to the new `api.rst` page in the `toctree`.

This results in a cleaner, more organized, and complete documentation site.

docs/api.rst

@@ -0,0 +1,10 @@
+API Reference
+=============
+
+This page contains the auto-generated API reference for the MedicalLib C++ library.
+
+.. doxygenfile:: MedicalLib/MedicalLib.h
+   :project: MedicalLib
+
+.. doxygenfile:: MedicalLib/Patient.h
+   :project: MedicalLib

docs/index.rst

@@ -10,8 +10,4 @@ Welcome to MedicalLib's documentation!
    :maxdepth: 2
    :caption: Contents:
 
-API Reference
--------------
-
-.. doxygenfile:: MedicalLib/Patient.h
-   :project: MedicalLib
+   api