User Data Migration

[SebastianKrupinski]

Feature Request

As a Nextcloud user I want to be able to export my data from the NC instance

Describe the solution you'd like

Implement a migrator: https://docs.nextcloud.com/server/latest/developer_manual/digging_deeper/user_migration.html#register-a-migrator

Work packages

• Migrate events
• Migrate appointment configurations
• Migrate proposals
• User manual documentation