Support the use of configuration file in hexapod low-level controller. MOOG provided the middleware wrapper originally that allows the user to update the configuration file by SAL. T&S team replaced it and used the Python CSC based on ts_salobj instead. This new CSC does not allow to do so. Therefore, this task will update the low-level controller code to let the user can configure the hexapod by the configuration file. This task also removes the dependency of /nfsdemo directory.