Convert impossible (due to melt dates) character cultures at startup

german/dutch defaults are reverse-melted before 1170/1150 based upon
character locale.

Startup event isn't actually referenced by a historical character yet
(and thus is never called), as I need to pick an ID and such. The
startup design is intended to initialize before all other possible
HIP mods can invoke their own 'Adapting History...' events. The
special character will live alone in history/characters/Logic.txt.