Improve import from VideoPsalm to include chords, song numbers and verse/chorus tags.

[PhilippeM1970]

Importer should import far more information than it does.

At most song numbers should be imported as well a chorus/verse tags. I have not yet checked if it is realted to the fact that I have set the UI in French in VideoPsalm or lazyness of the one who write import code but if we choose a free presentation program, obvioulsy we dont want to pass hundreds of hours to do that by hands...

While it is possible to use imported result, it is far from optimal... Ideally, a good importer would even allows to import background and other formatting options.