Move CInputManager from singleton to CApplication member

The main reason why CInputManager was singleton is the easy access across
the code. That had the negative side effect that time of destruction was
at a very late stage of the shutdown and could not be controlled by us.
My moving it to CApplication, the access is equally easy (using sApp) and
allows to be cleaned up properly during graceful shutdown.

ref T391

src/blackcore/application.cpp

@@ -163,7 +163,6 @@ namespace BlackCore
 
             this->initNetwork();
 
-
             // global setup
             m_setupReader.reset(new CSetupReader(this));
             connect(m_setupReader.data(), &CSetupReader::setupHandlingCompleted, this, &CApplication::onSetupHandlingCompleted, Qt::QueuedConnection);
@@ -179,7 +178,8 @@ namespace BlackCore
 
             if (!this->getApplicationInfo().isUnitTest())
             {
-                CInputManager::instance()->createDevices();
+                m_inputManager = new CInputManager(this);
+                m_inputManager->createDevices();
             }
         }
     }
@@ -985,7 +985,7 @@ namespace BlackCore
 
         // Release all input devices to not cause any accidental hotkey triggers anymore.
         // This is also necessary to properly free platform specific instances at a defined point in time.
-        CInputManager::instance()->releaseDevices();
+        if (m_inputManager) { m_inputManager->releaseDevices(); }
 
         // mark as shutdown
         if (m_networkWatchDog) { m_networkWatchDog->gracefulShutdown(); }
@@ -1002,8 +1002,6 @@ namespace BlackCore
 
         // from here on we really rip apart the application object
         // and it should no longer be used
-        sApp = nullptr;
-        disconnect(this);
 
         if (this->supportsContexts())
         {
@@ -1031,6 +1029,11 @@ namespace BlackCore
         }
 
         m_fileLogger->close();
+
+        qApp->sendPostedEvents(nullptr, QEvent::DeferredDelete);
+
+        sApp = nullptr;
+        disconnect(this);
     }
 
     void CApplication::onSetupHandlingCompleted(bool available)