feat(PreviewCard): support PeerTube mp4

[GeopJr]

fix: #244 (comment)

Two blockers:

• most instances DO NOT provide files, instead they rely on streaming mostly - the blender instance does provide files however (for testing)
• while seeking works when they are used, the video seems to stop updating after a while (audio still plays)

either will have to wait for #245 (comment) to be fixed and see if using inpustreams fixes the second point or try and figure out how to get Gtk.Video to use hlssink

I don't think we should create a custom video player.