Warn when information in install-config is ignored

Not all information provided in the install-config gets passed through to assisted-service.

An example is that platform settings other than the VIPs are ignored. So are the "capabilities". There may be others - we need to do a thorough audit.

If the user supplies data that we then ignore, we should log a warning. However, we must not return an error, because this may prevent people using their existing install-configs with the agent install method.