Improve Lookup Server

[AndyScherzinger]

• [x] https://github.com/nextcloud/lookup-server/issues/72
• [ ] https://github.com/nextcloud/lookup-server/issues/73
• [ ] https://github.com/nextcloud/lookup-server/issues/74
• [ ] https://github.com/nextcloud/lookup-server/issues/77
• [ ] https://github.com/nextcloud/lookup-server/issues/78
• [ ] https://github.com/nextcloud/lookup-server/issues/79
• [ ] https://github.com/nextcloud/lookup-server/issues/71