Allow overriding the config directory, not just the config file

Allow overriding the config directory, not just the config file: a task in MiMo-V2.6-RL-harbor-code: MiMo-V2.6-RL Code (Harbor) (Harbor dataset). Right now the only way I can override where the CLI keeps its config is the --configuration flag, which expects the full path to the config file, e.g.