Use file-based eventer for integration tests

This adds several top-level Podman flags for specifying different
events backend types, which are then used in CI. It resolves a
number of serious issues with events-based testing.

Signed-off-by: Matthew Heon <matthew.heon@pm.me>

libpod/container_api.go

@@ -187,7 +187,7 @@ func (c *Container) StopWithTimeout(timeout uint) error {
 		c.state.State == ContainerStateExited {
 		return ErrCtrStopped
 	}
-	defer c.newContainerEvent(events.Stop)
+
 	return c.stop(timeout)
 }