Moved the database class into its own subfolder.

scripts/wichtelbot.ts

scripts/wichtelbot/database/database.ts

scripts/wichtelbot/message/messageHandler.ts

scripts/wichtelbot/message/modules/assignmentModule.ts

scripts/wichtelbot/message/modules/generalModule.ts

scripts/wichtelbot/message/modules/informationModule.ts

tests/performance/assignment.ts

tests/performance/database.ts

tests/tests/messages/statefulCommands.ts

tests/tests/messages/statelessCommands.ts

tests/tests/wichtelbot.database.ts

tests/tests/wichtelbot.message.handler.ts

tests/tests/wichtelbot.message.module.assignment.ts

tests/utility/message.ts