tmpfiles-maui.conf: New file, used to ensure /var/log/journal exists

We need the journal on by default, but the OS installer may not have
created it.  Ensure it exists.
Enable important services by default

Some services, such as comman, needs to be enabled by default.
passwd: Add user and group for maui-initial-setup

Initial setup will run with its own user, so we add user and group.
passwd: Add avahi{,-daemon] and systemd-journal

Add users and groups for avahi{,-daemon] and systemd-journal.
Add bootloader installation service

Build system uses this.