Rewrite Save Data & Impl Save Data Dialog (#824)

* core: Rewrite PSF parser & add encoder

add .sfo hex pattern to /scripts

* core/fs: allow to mount path as read-only

* common: Add CString wrapper to handle native null-terminated strings

* SaveData: rewrite to implement full functionality

* mock value for SYSTEM_VER

* SavaData: backup features

* SavaData: SaveDataMemory features

* imgui Ref-counted textures

- has a background thread to decode textures

* imgui: rework gamepad navigation

* PSF: fixed psf not using enum class for PSFEntryFmt (was a standard old ugly enum)

- Add null check to CString when itself is used in a nullable field

* SaveDataDialog implementation

- Fix Mounting/Unmounting check of SaveInstance

src/common/io_file.cpp

@@ -396,4 +396,18 @@ s64 IOFile::Tell() const {
     return ftello(file);
 }
 
+u64 GetDirectorySize(const std::filesystem::path& path) {
+    if (!fs::exists(path)) {
+        return 0;
+    }
+
+    u64 total = 0;
+    for (const auto& entry : fs::recursive_directory_iterator(path)) {
+        if (fs::is_regular_file(entry.path())) {
+            total += fs::file_size(entry.path());
+        }
+    }
+    return total;
+}
+
 } // namespace Common::FS