Merge branch '2.2' into 3.0

# Conflicts:
#	gns3server/compute/qemu/qemu_vm.py
#	gns3server/handlers/api/controller/server_handler.py
#	gns3server/schemas/project.py
#	gns3server/schemas/qemu.py
#	gns3server/schemas/qemu_template.py
#	gns3server/version.py
#	tests/handlers/api/compute/test_qemu.py

gns3server/controller/__init__.py

@@ -172,7 +172,7 @@ class Controller:
 
         # remove all projects deleted from disk.
         for project in self._projects.copy().values():
-            if not os.path.exists(project.path):
+            if not os.path.exists(project.path) or not os.listdir(project.path):
                 log.info(f"Project '{project.name}' doesn't exist on the disk anymore, closing...")
                 await project.close()
                 self.remove_project(project)