fix: generate wfbench parameters using task.name keys

[ftschirpke]

This PR replaces task.category with task.name as the key used in the dictionaries the user can use to parameterize wfbench for different tools.
This replacement is sensible, or even necessary, due to the task.category being generated as None.
They lookup key being None for each task would render such an user-supplied dictionary useless.