Currently we allow the assisted-service to generate the InfraEnv ID automatically when the InfraEnv is created. The agents then have to fetch the list of InfraEnvs from the service to get the ID. This is suboptimal in a number of ways and won't be possible at all once we have authentication enabled on the assisted-service API.

Instead, modify assisted-service to accept an environment variable that contains a fixed InfraEnv ID. Any new InfraEnv created will use this ID (this has the desirable side effect that there can be only one InfraEnv).

Pre-generate a random ID in the command-line tool and store it in the configuration of both the agent and the assisted-service in the ISO.