Manager: Implement double-clicking a VM entry to start a VM

(and on Windows, bringing it to front if already running)

src/qt/qt_vmmanager_main.cpp

@@ -123,6 +123,8 @@ VMManagerMain::VMManagerMain(QWidget *parent) :
         ui->listView->setCurrentIndex(first_index);
     }
 
+    connect(ui->listView, &QListView::doubleClicked, this, &VMManagerMain::startButtonPressed);
+
     // Load and apply settings
     loadSettings();
 

src/qt/qt_vmmanager_system.cpp

@@ -408,6 +408,15 @@ VMManagerSystem::launchMainProcess() {
             return;
         }
     }
+    // If the system is already running, bring it to front
+    if (process->processId() != 0) {
+#ifdef Q_OS_WINDOWS
+        if (this->id) {
+            SetForegroundWindow((HWND)this->id);
+        }
+#endif
+        return;
+    }
     setProcessEnvVars();
     QString program = main_binary.filePath();
     QStringList args;