Create grub_backgroundimage_changer.py

This script will change the background picture displayed by grub, every time the system boots (provided the system is booted into atleast one of the operating systems)
The grub configuration file should be alterd accordingly ( In this case file 1.png will be displayed)
The pictures that are to be displayed are put in a folder, they are named "1", "2", "3" etc with their corresponding extensions initially. The script renames them every boot, thus a new picture will have the file name 1.png