Avoid host filesystem permissions and polluting home folder as much as possible

One of the things I love about Flatpaks is that they typically don't pollute the home directory, as all their configuration and data files go into their own directory within `~/.var`. I've noticed that with this package, a `~/Unity` directory is created, polluting the home directory. I'd really like to avoid this.

I understand that this package has access to the host filesystem, and Unity Hub wants to create that directory, so it does as it has access. Presumably, taking away access to the host filesystem would break the app in some way as it isn't able to properly handle it?

I feel like I've seen some Flatpak apps though that have access to the host filesystem, while still storing their own things within `~/.var`. Could this package be configured to do the same thing? Wouldn't it just be a matter of the app being told that `~/.var/com.unity.UnityHub/` is its home directory, while still having full filesystem access?

Thanks.

Bắt đầu bằng việc xem xét cấu hình Flatpak của gói và cách Unity Hub chọn thư mục home của mình. Kiểm tra xem việc chuyển home của ứng dụng vào ~/.var/com.unity.UnityHub/ có duy trì quyền truy cập cần thiết vào hệ thống tệp của host hay không, sau đó xác minh rằng ~/Unity không còn được tạo mà không làm hỏng ứng dụng.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.