dkms should use dpkg-divert to move modules from linux-image aside

[anbe42]

On Debian and derivatives, there is dpkg-divert which can be used to move package-provided files aside.

This should be used (when available and when acting on a linux-image package installed as .deb) to make the backups when dkms replaces a .ko file.

[LebedevRI]

This issue is marked as the upstream issue for https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1108359,
which is a bugreport.

I'm also hitting this issue with bcachefs DKMS module, it makes impossible to perform piuparts testing.