This isn’t used yet, but will be soon. It encapsulates an
`ActUserManager` with an `MctCarousel` to provide an all-inclusive
widget for selecting a user account.
It’s based off code from the user accounts panel of
gnome-control-center, licenced as GPLv2+, and authored by many people
over time (see
https://gitlab.gnome.org/GNOME/gnome-control-center/commits/master/panels/user-accounts).
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Philip Withnall