Tabular coach reports can now be generated for playlists as well as topics

Is this on the right track to resolve #2808?
Wondering if it might be confusing having two different drop downs - maybe check if there are groups, and then do one thing if there are playlists, and another if there are not and there are topics?

I think this should work for Nalanda-RCT3, and then when this is merged to develop, there should be no playlists, so it should have no immediate effect.

@aronasorman Can you confirm that we have no hardcoded playlists in develop?