Add a custom cleaner to clear cache for all flatpak applications

[ZakariaHassine]

There is a feature on GNOME Settings but only for every flatpak application individually : GNOME Settings > Apps > [a_flatpak_app] > Storage > Clear Cache...
It deletes these directories "~/.var/app/*/cache/".

[ZakariaHassine]

I have already made a custom cleaner (a very simple one). I have tested it on my part with no issues (and claimed back gigabytes of wasted space).
I don't know how to use GitHub so I'm putting the ".txt" file here.
flatpak.txt