Extend the scope of "Execute Shell Scripts" to cover not only scripts, but all executable files

Version information

thunar a8be9731

Steps to reproduce

Copy some binary, e.g.:

cp /usr/bin/galculator ~

Open thunar on ~ and double-click the binary

Current behavior

The binary will be executed

Expected outcome

The setting from edit --> preferences --> advanced called "Execute Shell scripts" [Never|ALways|Ask Every Time] should be considered as well for that binary

Additional information

Original discussion: xfdesktop#418