Better locations for the "My *" symlinks

[bochecha]

I tried building my first winepak app (not my first flatpak app though) and I'm getting to a point where it sort of works, and I can play the game.

However, I found every time I quit and relaunch, all my saves are lost.

That's because the game saves its data in C:\users\mathieu\My Documents\, which inside the sandbox is a symlink to my $HOME.

As a result, to make saves persistent I have to give the app the --filesystem=home finish arg. That's not great, I'd rather the app not access my home dir and all my documents.

could we make the C:\users\mathieu\My * symlinks instead point to some folders inside ~/.var/app/${appid}/data? That would make the data persistent between multiple app runs, without giving it access to the whole home dir.

(I'm not sure this is the right place for this bug report, I'm not doing anything with those symlinks in the app manifest so I'm assuming they are set up in the Sdk)