* Implement basic support of SystemSaveData and Cleanup IFileSystemProxy
- Implement `OpenSystemSaveData` as a `IFileSystem` in `SaveHelper`:
On real device, system saves data are stored encrypted, and we can't create an empty system save data for now. That's why if a user put his own dump of system save in `RyuFs\nand\system\save\`, we extract content in associated folder and open it as a `IFileSystem`. If the system save data don't exist, a folder is created.
- Cleanup `IFileSystemProxy` by adding a Helper class.
- Implement `GetSavePath` in `VirtualFileSystem` and remove `GetGameSavePath` in `SaveHelper`.
* remove the forgotten I
* Fix align
