code: public Optional<PluginWrapper> getPluginWrapper(AddOnModel addOnModel) {
          return Optional.of(pluginWrappers.get(addOnModel));
      }
docs: Returns the (optional) PluginWrapper for the AddonModel.
  If the return is empty, it means that the AddOn was not loaded through pf4j
  
  @param addOnModel the AddOnModel
  @return the PluginWrapper if loaded through pf4j or empty if added as an argument