HltEventLoopMgr: Use worker ID as directory name
- Add worker ID as a private member and read from DF config
- Use the worker ID instead of the application name as the per-worker directory name
- Remove unused properties: PartitionName, JobOptionsType, enabledROBs, enabledSubDetectors
- Convert the ApplicationName property to a plain private member
- Avoid code-duplication when reading properties from DataFlowConfig