Add -f format option for get, add & upd calls

[rgstephens]

Currently there are two commands to get stories, getstories and getstoriesmd. Change this to a single command with a -f md and -f json options to specify the requested format. This is consistent with the rasa data command option.

[webgem-jpl]

+1 for this feature.

The output in json format from Rasa-x endpoint is currently not in order of Ids, which makes the transformation to markdown inconsistent. I would like to have the json output and its corresponding markdown output in order of ids by default.

I would also want that functionality to be extended for the annotations endpoint.