FilePoller: Made `files` a mandatory parameter.
FilePoller: Made `files` a mandatory parameter.

Changed the `files` parameter to be mandatory and added check to
ensure that at least one file is passed in configuration otherwise
the instrument crashes.

bjackman/workload-automation,Sticklyman1936/workload-automation,jimboatarm/workload-automation,jimboatarm/workload-automation,bjackman/workload-automation,bjackman/workload-automation,jimboatarm/workload-automation,Sticklyman1936/workload-automation,jimboatarm/workload-automation,jimboatarm/workload-automation,bjackman/workload-automation,bjackman/workload-automation,bjackman/workload-automation,Sticklyman1936/workload-automation,Sticklyman1936/workload-automation,Sticklyman1936/workload-automation,jimboatarm/workload-automation,Sticklyman1936/workload-automation