A way to have a qube close once all its windows are closed?

[Stumpy]

I usually have lots of windows open but am finding that after a few days
I have lots of appvms open that arent being used... usually finding this
when i try to open (yet another) appvm and being told I am out of memory.
I have maxed out my memory slots, and shaved each appvm down to the
minimum amount of memory that it needs to operate so...

Is there a way, like dispVMs, to have an appvm automatically close when
its not in use? "In use" defined as not having a window open?

[Ivan Mitev]

See https://github.com/QubesOS/qubes-app-shutdown-idle

and the related issue:

https://github.com/QubesOS/qubes-issues/issues/832#issuecomment-437303826