Use custom postinst to fix long delay when first installing 46

Jeremy Bícharequested to merge
wip/postinst into debian/latest

Closes https://bugs.debian.org/1070119

@smcv Are you able to review this?

I think we can assume that people using gnome-remote-desktop are using systemd which simplifies this compared to polkitd.postinst

Merge request reports