Issue #464. Save player and city stats on the database
Issue #464. Prepare the city statisticts and cleanup naming inconsistencies with clientServerEventBus
Issue #464. Integrate the dumped database in the savegame
Issue #464. Introduce database service for dumping and restoring database.
Issue #777. Store the savegame in an archive
Issue #755. Add the dialog in game and fix some found issues
Issue #755. Add contract broker dialog
Issue #765. Add additional tests and update test documentation
Issue #782
Issue #748. Wrap the message in a target event