Warn if the settings in the workflow are from higher versions

If we open some newer workflow on old Orange, the results are undefined. It could work, it might crash, or it could load but not work properly (forgets some settings).

On loading settings we should confirm that the setting version of the available widget is higher or equal to the saved setting version. If not, we should warn the user, and (if possible) show what to update (core orange or a specific add-on).

What to do after the warning? I do not know. I suggest we still try to use the settings as they are. If it crashes, well, fine, there was a warning.

Start by locating the workflow settings-loading path and the code that compares saved settings with the available widget version. Done means an older Orange installation warns when saved settings require a higher widget version, identifies the core Orange or add-on to update when possible, and preserves the proposed attempt to load the settings.

Written by the indexing model from the issue text.