Reconsider filesystem=home permision

[Tiagoquix]

I think using filesystem=home by default is too broad. We should probably prefer the Flatpak portal where it gives access to specific files (and also prefer user overrides for specific folders, of course).

[kjarosh]

Ruffle does support XDG portals, however as of now it's problematic to disable that permission, as movies can load other files next to them. We need to add proper UI and support for loading multi-file movies.

Currently, we use filesystem=home permission, although Ruffle will ask if a movie wants to access a file outside of the directory where the movie is located.

[Tiagoquix]

An user can have movie files in /media/MyDrive/Ruffle_files, for example. He would need to add an override and filesystem=home wouldn't suffice by default.

One thing we can do is use a specific folder for Ruffle files and tell users to use it the first time the app is opened. Such as:

This Flatpak version of Ruffle is sandboxed and only reads files from `$HOME/Videos/Ruffle Movies` by default.
You can add a Flatpak override to allow Ruffle to access other locations, and you can also change the setting for the default folder in the options.

With that, a new setting would also be created, called "Default folder", and it would be basically the folder that opens by default when Ruffle accesses the file picker (it would also create the folder if it does not exist when opening the app).

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The ideal solution, of course, would be that when a file is selected Ruffle gains access to all the files in that file's folder, so it would deal with the problem of movies loading other files next to them. This way, it uses "Flatpak documents" and files are stored temporarily in /run/user/1000/doc or something similar.

[torokati44]

See: flatpak/xdg-desktop-portal#463