fw/workload: Use apk version for workload if not set.
fw/workload: Use apk version for workload if not set.

If a workloads `version` attribute is not set, and an APK file is
found, use this as the version number. This allows for workloads to not
specify a default version via parameters and for an available APK to be
automatically chosen.

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