feat: add incus auto-client certificate trust (#406)

- add fact to export vault public cert from agents
- add fact to export list of trusted incus client certs
- add method for incus clients to export their client cert to be trusted

Reviewed-on: #406

modules/incus/manifests/client.pp

@@ -0,0 +1,16 @@
+# incus::client
+#
+# This class configures a host as an incus client and exports its certificate
+# for automatic trust management on incus servers.
+#
+class incus::client {
+
+  # Export this client's certificate for collection by incus servers
+  @@incus::client_cert { $facts['networking']['fqdn']:
+    hostname    => $facts['networking']['fqdn'],
+    certificate => $facts['vault_cert_content'],
+    fingerprint => $facts['vault_cert_fingerprint'],
+    tag         => 'incus_client',
+  }
+
+}