Enable selecting flatpak available packages on any distro IF Flatpak is selected for installation

[ridiaconu]

As of now I can install flatpak separately but I don't have any option to select flatpak packages after its installation.

Since most of the packages are available on flatpak, it would be nice to add an option to be able to select flatpak packages IF flatpak is checked for installation

[vicholz]

+1