conf: Extract code to filter domain list into a separate function
conf: Extract code to filter domain list into a separate function

Separate the code to simplify future refactors.

taget/libvirt,taget/libvirt,zippy2/libvirt,jfehlig/libvirt,jardasgit/libvirt,fabianfreyer/libvirt,rlaager/libvirt,eskultety/libvirt,eskultety/libvirt,andreabolognani/libvirt,libvirt/libvirt,agx/libvirt,jardasgit/libvirt,eskultety/libvirt,crobinso/libvirt,agx/libvirt,olafhering/libvirt,eskultety/libvirt,eskultety/libvirt,nertpinx/libvirt,olafhering/libvirt,datto/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,datto/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,olafhering/libvirt,jardasgit/libvirt,nertpinx/libvirt,crobinso/libvirt,rlaager/libvirt,taget/libvirt,andreabolognani/libvirt,rlaager/libvirt,andreabolognani/libvirt,libvirt/libvirt,agx/libvirt,jfehlig/libvirt,datto/libvirt,datto/libvirt,taget/libvirt,libvirt/libvirt,olafhering/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,crobinso/libvirt,fabianfreyer/libvirt,VenkatDatta/libvirt,jardasgit/libvirt,zippy2/libvirt,rlaager/libvirt,VenkatDatta/libvirt,agx/libvirt,agx/libvirt,nertpinx/libvirt,crobinso/libvirt,taget/libvirt,libvirt/libvirt,nertpinx/libvirt,rlaager/libvirt,jardasgit/libvirt,jfehlig/libvirt,andreabolognani/libvirt,datto/libvirt,fabianfreyer/libvirt,jfehlig/libvirt,zippy2/libvirt,VenkatDatta/libvirt,zippy2/libvirt