[desktop] Initial data manager prototype

Right now, all this adds is a small dialog to the Widgets frontend
showing the user how much space is taken up by their saves, shaders,
NAND, and mods. It also gives them the choice to clear these directories
(with 2x confirmation), OR open the directory in their system file
manager.

In the future, a lot more can be done with this concept. Notably, a
common import/export (a la android) could be added, the UI can obviously
be polished, etc. We could also add this to Android, but I don't think
common import/export is needed *for* Android, and should probably be
left in qt_common.

Signed-off-by: crueter <crueter@eden-emu.dev>

src/qt_common/qt_string_lookup.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include <QString>
+#include <frozen/string.h>
+#include <frozen/unordered_map.h>
+#include <qobjectdefs.h>
+#include <qtmetamacros.h>
+
+namespace QtCommon::StringLookup {
+
+Q_NAMESPACE
+
+// TODO(crueter): QML interface
+enum StringKey {
+    SavesTooltip,
+    ShadersTooltip,
+    UserNandTooltip,
+    SysNandTooltip,
+    ModsTooltip,
+};
+
+static constexpr const frozen::unordered_map<StringKey, frozen::string, 5> strings = {
+    {SavesTooltip, "DO NOT REMOVE UNLESS YOU KNOW WHAT YOU'RE DOING!"},
+    {ShadersTooltip, "Shader pipeline caches. Generally safe to remove."},
+    {UserNandTooltip, "Contains updates and DLC for games."},
+    {SysNandTooltip, "Contains firmware and applet data."},
+    {ModsTooltip, "Contains all of your mod data."},
+};
+
+static inline const QString Lookup(StringKey key)
+{
+    return QString::fromStdString(strings.at(key).data());
+}
+
+}