mimeapps: Prefer GNOME Software for .debs
In May 2005, File Roller was added as the default handler for a number of "new mime types supported in GNOME 2.10", including application/x-deb.0 At some point in the intervening 16¾ years, GNOME Software was created and taught how to install .deb files.
GNOME Software is a better handler for .deb files than File Roller, for two reasons:
- gnome-software is required by gnome-core, whereas file-roller is required only by the larger gnome metapackage. So Software is more likely to be installed.
- Software can actually install .debs, whereas File Roller shows a pair of confusing sub-archives.