Ghostrider ignores Environmnent Variables in config.json
When ghostrider algorithm is used the enviroment variables in config.json are not expanded.

When running randomx the correct worker ID is showed at pool's interface but when running ghostrider the worker is showed as ${HOSTNAME}.

The worker ID is configured at user's variable:
     "user": "XxXxXxXxXxXxXx.${HOSTNAME}"
