[Feature] - Database expansion

[Cinnazeyy]

Implement support for the following new tables:

• api_keys
• plotsystem_buildteams
• plotsystem_builder_is_reviewer
• plotsystem_buildteam_has_countries

As well as add support for the following new colum in table "plotsystem_countries":

• continent

Link to whole updated database scheme

Also keep in mind backwards compatibility!

[jokil123]

api_keys was renamed to plotsystem_api_keys. the current database model should look like this: https://github.com/AlpsBTE/Plot-System-API/blob/main/migrations/20220517070321_database_schema_setup.sql