message: Add more verbose logging to dataman when loading manager libraries
diff: struct DataManBase::ManagerLibrary
  {
  + std::string m_LibraryName;
  adios2sys::DynamicLoader::LibraryHandle m_LibraryHandle;
  DataManBase *(*m_getManFunc)();
  @@ -86,6 +87,7 @@ struct DataManBase::ManagerLibrary
  libName);
  }
  m_getManFunc = reinterpret_cast<DataManBase *(*)()>(symbolHandle);
  + m_LibraryName = libName;
  }
  ~ManagerLibrary()
  @@ -319,6 +321,11 @@ std::shared_ptr<DataManBase> DataManBase::get_man(std::string method)
  libIt =
  m_LoadedManagers.insert({method, new ManagerLibrary(method)})
  .first;
  + logging("Loaded " + libIt->second->m_LibraryName);
  + }
  + else
  + {
  + logging("Using existing " + libIt->second->m_LibraryName + ".");
  }
  return std::shared_ptr<DataManBase>(libIt->second->m_getManFunc());
  }
  