[Task] - Database Rework

[Cinnazeyy]

Rework the entire database and refactor the related code to bring it up to standards and fix long running issues.
New database model is documented at Plot-System-DB

Most important changes:

• CityProject, Difficulties, etc. no longer store name and description in db, instead they have a string id which will be used to get a translated name & description
• entirely new review system (details still WIP)
• review history
• plot schematics are now saved in the database and no longer need to be transfered using ftp or symlink
• most tables are stored in models and cached to reduce the amount of sql querries by a large margin
• bundle all sql statements in DataProviders for the respective table to separate data and logic layers
• support custommodel data and generic materials additionally to headdb heads for the country items
• cleanup and refactor lots of smaller things
• no longer support loading plots below plot version 3
• completed schematic is now created with the correct y height.