feat: add incus auto-client certificate trust

- 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

modules/libs/lib/facter/vault_cert_content.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+# lib/facter/vault_cert_content.rb
+
+Facter.add(:vault_cert_content) do
+  confine kernel: 'Linux'
+  setcode do
+    cert_path = '/etc/pki/tls/vault/certificate.crt'
+    File.read(cert_path) if File.exist?(cert_path) && File.readable?(cert_path)
+  end
+end