roles/install_arch: Make use of systemd-firstboot

Sets a bunch of settings at once.

roles/install_arch/tasks/main.yml

@@ -106,8 +106,14 @@
   shell: mdadm --detail --scan >> /mnt/etc/mdadm.conf
   when: filesystem == "ext4"
 
-- name: set the hostname
-  lineinfile: dest=/mnt/etc/hostname line="{{ hostname }}" create=yes
+- name: configure locale.gen
+  lineinfile: dest=/mnt/etc/locale.gen line="en_US.UTF-8 UTF-8"
+
+- name: run locale-gen inside chroot
+  command: chroot /mnt locale-gen
+
+- name: run systemd-firstboot
+  command: chroot /mnt systemd-firstboot --locale=en_US.UTF-8 --timezone=UTC --hostname={{ hostname }}
 
 - name: add mdadm_udev to mkinitcpio.conf
   lineinfile:
@@ -132,15 +138,6 @@
 - name: configure grub
   command: chroot /mnt grub-mkconfig -o /boot/grub/grub.cfg
 
-- name: configure zoneinfo
-  file: src=/usr/share/zoneinfo/UTC dest=/mnt/etc/localtime state=link force=yes
-
-- name: configure locale.gen
-  lineinfile: dest=/mnt/etc/locale.gen line="en_US.UTF-8 UTF-8"
-
-- name: run locale-gen inside chroot
-  command: chroot /mnt locale-gen
-
 - name: enable services inside chroot
   command: chroot /mnt systemctl enable sshd systemd-networkd systemd-resolved