feat: allow for custom registry

This patch adds a simple CLI which can mirror all the images needed
as well as allow for simple override for `atmosphere_image_repository`
for all images.
diff --git a/roles/ipmi_exporter/tasks/main.yml b/roles/ipmi_exporter/tasks/main.yml
index bcc25d8..31cd4c4 100644
--- a/roles/ipmi_exporter/tasks/main.yml
+++ b/roles/ipmi_exporter/tasks/main.yml
@@ -47,7 +47,7 @@
             spec:
               containers:
                 - name: exporter
-                  image: "{{ ipmi_exporter_image_repository }}/ipmi-exporter:{{ ipmi_exporter_image_tag }}"
+                  image: "{{ lookup('vexxhost.atmosphere.image_ref', 'prometheus_ipmi_exporter', output='ref') }}"
                   ports:
                     - name: metrics
                       containerPort: 9290