Migration of the condition data

[Cyperghost]

Ref #5984

With the overhaul of the condition system, the current data must be migrated to the new format.
This means that condition types of plugins that have already been created, e.g. for Automatic user group assignment or Notes, cannot be migrated correctly. At the time of the upgrade, the plugins are not up to date with the new condition system. It may also be the case that condition types that were added by plugins are no longer offered or have not yet been migrated.
This would mean that the filtering by the condition system would no longer work as before the update, e.g. users could be added to a user group that were not previously added.