Add GTK application implementation

internal/gui/shortcutsdialog.go

@@ -0,0 +1,23 @@
+package gui
+
+import (
+	"github.com/diamondburned/gotk4/pkg/gtk/v4"
+	"suruatoel.xyz/mcg/data"
+)
+
+type shortcutsDialog struct {
+	*gtk.ShortcutsWindow
+}
+
+func newShortcutsDialog() *shortcutsDialog {
+	dialog := shortcutsDialog{}
+	dialog.loadWidgets()
+
+	return &dialog
+}
+
+func (d *shortcutsDialog) loadWidgets() {
+	builder := gtk.NewBuilderFromString(data.ShortcutsDialogXML)
+
+	d.ShortcutsWindow = builder.GetObject("McgShortcutsDialog").Cast().(*gtk.ShortcutsWindow)
+}