feat: install vault-plugin-secrets-litellm

ensure the litellm plugin for vault is installed

hieradata/roles/infra/storage/vault.yaml

@@ -28,3 +28,4 @@ profiles::nginx::simpleproxy::proxy_path: '/'
 
 profiles::packages::include:
   openbao-plugins: {}
+  vault-plugin-secrets-litellm: {}