override LFN in Workload

After #4053, Workload internal LFN override what the Tier0 configures in the Spec.
Override the Workload LFNs back and also pass the run number to construct the
Tier0 specific LFN with directories based on the run number.
Merge pull request #4058 from hufnagel/tier0-lfn

override LFN in Workload