need to add .mpg extension to the cleaning task

[hhrhhr]

I believe that here:

https://github.com/motioneye-project/motioneye/blob/b2fbf8aef3f203f7f5c5f8f00d82dfeab14ac863/motioneye/mediafiles.py#L45

Now timelapse video added through the configuration of the camera (timelapse_codec mpg) is not removed automatically.

[MichaIng]

Thanks for reporting. Makes sense to add all new possible file formats.