container stop: release lock before calling the runtime

Podman defers stopping the container to the runtime, which can take some
time.  Keeping the lock while waiting for the runtime to complete the
stop procedure, prevents other commands from acquiring the lock as shown
in #8501.

To improve the user experience, release the lock before invoking the
runtime, and re-acquire the lock when the runtime is finished.  Also
introduce an intermediate "stopping" to properly distinguish from
"stopped" containers etc.

Fixes: #8501
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

libpod/define/containerstate.go

@@ -28,6 +28,9 @@ const (
 	// ContainerStateRemoving indicates the container is in the process of
 	// being removed.
 	ContainerStateRemoving ContainerStatus = iota
+	// ContainerStateStopping indicates the container is in the process of
+	// being stopped.
+	ContainerStateStopping ContainerStatus = iota
 )
 
 // ContainerStatus returns a string representation for users
@@ -50,6 +53,8 @@ func (t ContainerStatus) String() string {
 		return "exited"
 	case ContainerStateRemoving:
 		return "removing"
+	case ContainerStateStopping:
+		return "stopping"
 	}
 	return "bad state"
 }