GH-338, GH-513, GH-700 Unify edit instance with console window

* The resulting instance window can be closed at any point.
* Main window is kept open and running instances are marked with a badge.
* Multiple instances can now run from the same MultiMC - it's even more **multi** now.
* MultiMC can be entirely closed, keeping Minecraft(s) running.

api/logic/minecraft/MinecraftInstance.cpp

@@ -465,7 +465,9 @@ std::shared_ptr<LaunchTask> MinecraftInstance::createLaunchTask(AuthSessionPtr s
 	{
 		process->setCensorFilter(createCensorFilterFromSession(session));
 	}
-	return process;
+	m_launchProcess = process;
+	emit launchTaskChanged(m_launchProcess);
+	return m_launchProcess;
 }
 
 QString MinecraftInstance::launchMethod()