Add cover image fuzzy mappings based on latest Wappukalenteri
Add cover image fuzzy mappings based on latest Wappukalenteri

NOTE/TODO: there are currently lots of events without cover image

kaupunki-apina/prahapp-backend,kaupunki-apina/prahapp-backend,futurice/wappuapp-backend,futurice/wappuapp-backend