Improve Default Training Language on Kata

[Kacarott]

The current behaviour (as I understand it) is that when visiting a kata page, the training language is automatically set to your "Last Trained Language" if that is available. However, if it is not available, then the language chosen will be the next language alphabetically after your last trained language, which is available, or if there are none, then simply the first language alphabetically, of all available.

I think this behaviour could be improved somewhat. My suggestion for criteria of how the default training language should be selected is as follows:

• If the user has an unfinished attempt in a language (ie. marked as yellow), then that language should be selected.
  • If the user has unfinished attempts in multiple languages, then the most recently trained of these should be selected (if this is not feasible to determine, then any would do).
• If there are no unfinished attempts, then the most recently trained language should be selected.
• If that is not available, then any available languages from a users Trained languages should be selected.
• Otherwise, pick any language (perhaps, the original language of the kata?)

I think this would lead to less confusing behaviour, and less accidental attempts in languages a user does not even train it.