zezere: role/playbook to deploy Zezere

Zezere is the Fedora IoT device provisioning service.  It is the
software that runs *provision.fedoraproject.org*, but it can be
self-hosted (if you can figure it out; there is no documentation
whatsoever).

The main use case for running Zezere locally is to automatically add
trusted SSH public keys to Fedora IoT devices, without depending on a
cloud service.  This playbook sets up Zezere with the very minimal
configuration needed to meet this goal.

roles/zezere/handlers/main.yml

@@ -0,0 +1,2 @@
+- name: relabel zezere data directory
+  command: restorecon -RF /var/lib/zezere