Sets up a login screen using tuigreet. From there the user is thrown
into a shell. Other units/services (usually, the user service `river`)
take care to start an actual wayland session for the user.
Creates separate snapper services for root and home directories. Does
_not_ yet set up any btrfs mounts or ensure that they are mounted at the
locations.
Instead of changing a line in the sudoers file we just copy a new
drop-in file into the sudoers.d/ dir. Easier, less error-prone and
allows everyone to see 'who' the sudo enabled users are (since it is
world readable).
User services under control of runit under turnstiled now default to the
`~/.local/state/service/` directory (and `~/.local/state/service-env/`
for the env vars). This mimics the system-wide runit setup, with service
templates kept in `/etc/sv` (in my case `~/.config/sv` for user
services) and active ones in `/var/service`
For now, putting the associated files simply within the books/ directory
as well is the simplest solution. It also removes some clutter from the
root directory. If we refactor later, this will be changed overall
anyway.
