Extract the list of files and packages on ospacks and images

Generate pkglist and filelist files indexing the contents of each artifact so you don't need to download, decompress and mount just to check what is being shipped.

This MR includes:

• ad22cbe7 images: Extract the list of packages
• 0d7785cb images: Extract the list of files
• be185072 ospack: Rework pkglist and filelist extraction
• 9b12bd18 ospack,sysroot: Append file extension automatically