table printer: Introduce a cell struct
table printer: Introduce a cell struct

No functional change here, simply some data structure reorg,
so we can have more data for each cell in the future.

matthiasclasen/flatpak,GeorgesStavracas/flatpak,GeorgesStavracas/flatpak,GeorgesStavracas/flatpak,handsome-feng/flatpak,matthiasclasen/flatpak,handsome-feng/flatpak,matthiasclasen/flatpak,flatpak/flatpak,GeorgesStavracas/flatpak,matthiasclasen/flatpak,flatpak/flatpak,flatpak/flatpak,handsome-feng/flatpak,flatpak/flatpak,flatpak/flatpak,handsome-feng/flatpak,matthiasclasen/flatpak,handsome-feng/flatpak,GeorgesStavracas/flatpak