Qt: fix opening folders by using util functions

[Megamouse]

No description provided.

[AniLeo]

Same issue

Log has

·! 0:00:10.668994 GUI: gui::utils::open_dir: About to open path '/home/ani/Games/BLES01227 - Asura's Wrath/PS3_GAME'

Terminal output has:

xdg-mime: no method available for querying MIME type of '/home/ani/Games/BLES01227 - Asura's Wrath/PS3_GAME'
xdg-mime: mimetype argument missing
Try 'xdg-mime --help' for more information.
/usr/bin/xdg-open: line 880: x-www-browser: command not found
XPCOMGlueLoad error for file /usr/lib/firefox/libmozgtk.so:
/usr/lib/libgio-2.0.so.0: undefined symbol: g_source_set_static_name
Couldn't load XPCOM.
/usr/bin/xdg-open: line 880: iceweasel: command not found
/usr/bin/xdg-open: line 880: seamonkey: command not found
/usr/bin/xdg-open: line 880: mozilla: command not found
/usr/bin/xdg-open: line 880: epiphany: command not found
/usr/bin/xdg-open: line 880: konqueror: command not found
/usr/bin/xdg-open: line 880: chromium: command not found
/usr/bin/xdg-open: line 880: chromium-browser: command not found
/usr/bin/xdg-open: line 880: google-chrome: command not found
/usr/bin/xdg-open: line 880: www-browser: command not found
/usr/bin/xdg-open: line 880: links2: command not found
/usr/bin/xdg-open: line 880: elinks: command not found
/usr/bin/xdg-open: line 880: links: command not found
/usr/bin/xdg-open: line 880: lynx: command not found
/usr/bin/xdg-open: line 880: w3m: command not found
xdg-open: no method available for opening 'file:///home/ani/Games/BLES01227%20-%20Asura's%20Wrath/PS3_GAME'

Same on Open Trophy Directory, Open Install Directory, Open Custom Config Folder

[Megamouse]

merging anyway

[tvoracek]

@Megamouse Why was this merged with so many issues?