topoSet: allow use of 'zone' instead 'set', 'zones' instead of 'sets' in all set sources

Summary

Everywhere a topoSetSource uses a (file-based) set allow use of a (mesh-based) zone.

Resolved bugs (If applicable)

Details of new models (If applicable)

If the keyword 'zone' is found instead of 'set' it instead uses the name to lookup the corresponding zone from the mesh. The advantage of a mesh-based zone is that they get updated if the mesh is updated.

Risks

Change to user input: everywhere in a topoSetDict can use 'zone' or 'zones' instead of 'set' or 'sets'.