fw/config: add get_config() to ConfigManager
fw/config: add get_config() to ConfigManager

Add a method to allow obtaining the combined config after config
manager has been finalized.

lisatn/workload-automation,ARM-software/workload-automation,setrofim/workload-automation,lisatn/workload-automation,ARM-software/workload-automation,ARM-software/workload-automation,setrofim/workload-automation,ARM-software/workload-automation,setrofim/workload-automation,lisatn/workload-automation,setrofim/workload-automation,lisatn/workload-automation