Allow loading of LTM exports to the Viewer, although the memory servers have not been started

Steps if you want to test:

• Make some memory export and store it somewhere on the FS
• Kill all memories. Only start armem core scenario
• Open memory viewer GUI, disable drop of disconnected memories
• load the export

If a memory server is running -> the imported data will be commited to the server (as before) If no memory server is running -> create a new virtual memory (only available in GUI) and show data there

source/RobotAPI/libraries/armem_gui/MemoryViewer.cpp

@@ -267,7 +267,7 @@ namespace armarx::armem::gui
         {
             std::stringstream ss;
             ss << "Memory name '" << memoryName
-               << "' is unknown. Known are: " << simox::alg::to_string(simox::alg::get_keys(memoryData), ", ");
+               << "' is unknown. Known are: " << simox::alg::join(simox::alg::get_keys(memoryData), ", ");
             statusLabel->setText(QString::fromStdString(ss.str()));
             return nullptr;
         }
@@ -406,10 +406,7 @@ namespace armarx::armem::gui
         TIMING_START(MemoryExport)
 
         std::string status;
-        std::vector<wm::Memory> memoryDataVec;
-        std::transform(memoryData.begin(), memoryData.end(), std::back_inserter(memoryDataVec),
-                       [](auto& el) { return el.second; });
-
+        std::vector<wm::Memory> memoryDataVec = simox::alg::get_values(memoryData);
         diskControl->storeOnDisk(directory, memoryDataVec, &status);
 
         statusLabel->setText(QString::fromStdString(status));