yuzu qt: Create shortcuts on Linux

This creates a Desktop Entry file and a PNG icon for the entry when the
user right-clicks a game and selects "Create Shortcut -> Create
{Application,Desktop} Shortcut". This uses the current executable's path
to create the shortcut.

yuzu qt: Add more error checking and OS gating for shortcuts

main: Remove FreeBSD gating for shortcuts

I'm not going to test FreeBSD, so I don't know if they follow
Freedesktop.org or not. I just have to let someone else verify that it
works there and let them enable it.

main: Move shortcut function to its own function

This function should really be in a common library, at least among
frontends.

main: Remove image manip references

main: Fix difference in MinGW and native GCC versions

main: Fix negation in creat shortcut

Addresses review comment

Co-authored-by: Jan Beich <jbeich@FreeBSD.org>

main: Re-enable freedesktop shorcuts for FreeBSD

src/yuzu/game_list.h

@@ -52,6 +52,11 @@ enum class DumpRomFSTarget {
     SDMC,
 };
 
+enum class GameListShortcutTarget {
+    Desktop,
+    Applications,
+};
+
 enum class InstalledEntryType {
     Game,
     Update,
@@ -108,6 +113,8 @@ signals:
                              const std::string& game_path);
     void DumpRomFSRequested(u64 program_id, const std::string& game_path, DumpRomFSTarget target);
     void CopyTIDRequested(u64 program_id);
+    void CreateShortcut(u64 program_id, const std::string& game_path,
+                        GameListShortcutTarget target);
     void NavigateToGamedbEntryRequested(u64 program_id,
                                         const CompatibilityList& compatibility_list);
     void OpenPerGameGeneralRequested(const std::string& file);