Fix Doxygen warnings

• Remove filtering warnings regarding missing MantleAPI documenation
• Remove Doxyfile exclusions for MantleAPI
• Fix doxygen warnings related to MantleAPI documenation

sim/src/core/opSimulation/framework/controller.h

 /*******************************************************************************
  * Copyright (c) 2021 in-tech GmbH
- *               2022-2023 Bayerische Motoren Werke Aktiengesellschaft (BMW AG)
+ *               2022-2024 Bayerische Motoren Werke Aktiengesellschaft (BMW AG)
  *
  * This program and the accompanying materials are made
  * available under the terms of the Eclipse Public License 2.0
@@ -45,6 +45,9 @@ public:
   //! @return System of an agent
   const System& GetSystem() const { return system; }
 
+  //! @brief Adds an entity to the controller
+  //!
+  //! @param entity The entity to be manipulated by the controller
   void AddEntity(Entity* entity)
   {
     entity->SetSystem(system);