make Mac address randomization a configurable feature on OS image creation

We often have to provide device WIFI MAC addresses to clients for whitelisting behind captive portals in order to connect the devices to their network. The MAC address randomization has thrown us off many times as we accidentally got an invalid WIFI MAC address from the device, introducing a lot of risk and insecurity into the deployment process. Currently deactivating this can only be achieved through command line intervention or config file editing, which is not particularly accessible for non developers