Location of the cluster-join-token.key file.
You can retrieve the contents of the file when creating a new agent via https://hercules-ci.com/dashboard.
As this value is confidential, it should not be in the store, but installed using other means, such as agenix, NixOps
deployment.keys, or manual installation.
The contents of the file are used for authentication between the agent and the API.
staticSecretsDirectory + "/cluster-join-token.key"