Install several Flatpaks at once

[Justinzobel]

Prerequisites

• I have searched open and closed issues for duplicates.

Feature

Add the capability to install multiple at once.

Situation: New install, want to install several flatpaks from flatpakref files I have stored on a separate drive.

Describe the solution you'd like
Select several .flatpakref files in chosen file manager, right click, open in Sideload, sideload shows you info on all apps selected and can tell you the full install size and proceed to install them.

Existing work
Not that I've seen.

Describe alternatives you've considered
If GUI is too much a CLI option, sideload flatpak1.flatpakref flatpak2.flatpakref flatpakn.flatpakref

Additional context
Keep up the good work.