validateConfig
Called from TorServiceConfig.Foreground.Companion.Builder and TorServiceConfig.Foreground.newEnvironment when checking the defaultConfig, or if a stand-alone Config is being used to create a new instance of TorRuntime.Environment.
Implementations MUST ensure all resources are configured correctly to inhibit an unrecoverable application state if TorServiceConfig, or TorRuntime.Environment is allowed to be instantiated with a non-operational component or resource.