Add "Set Default Application" feature in "Open with" submenu

Add new option "Set Default Application" in "Open with" submenu.

Add preselect_default_checkbox argument in thunar-chooser-dialog. If preselect_default_checkbox is TRUE then the thunar-chooser-dialog set selected application as default application.

Also change the title of thunar-chooser-dialog form "Open with" to "Set Default Application"