Modifying the Exec cmd in the desktop-files

Modifying the Exec cmd in the desktop-files

Fixup the *.desktop files and add a file handler to the Exec key.
https://specifications.freedesktop.org/desktop-entry-spec/latest/ar01s06.html

Gbp-Pq: Topic fixes
Gbp-Pq: Name Modifing-the-Exec-cmd-in-the-desktop-files.patch