pikvm: Add role/playbook for PiKVM

PiKVM comes with its own custom Arch Linux-based operating systems.  We
want to be able to manage it with our configuration policy, especially
for setting up authentication, etc.  It won't really work with the
host-provisioner without some pretty significant changes to the base
playbooks, but we can control some bits directly.

group_vars/pikvm.yml

@@ -0,0 +1,9 @@
+root_authorized_keys: |
+  {{ dustin_ssh_keys_sk }}
+
+root_password_hash: ''
+
+pikvm_users:
+- username: dustin
+  password: >-
+    {{ lookup('pipe','rbw get --folder Pyrocufflink ' + ansible_hostname + ' dustin') }}