Slicer sql denormalize fails with config error

[schwab]

At present many of the slicer commands (except serve) fail to run with or without specifying a config file path and always through an error indicating the config provider is of type str (or unicode).

[Stiivi]

(from the Gitter chat) Looks like in cubes.slicer.commands module all Workspace(config) have to be replaced with Workspace(read_config(config)).

[morrme]

@Stiivi I think this is something I can help with.