feat(carddav): Map user's additional emails into the SAB card

[ChristophWurst]

• Contributes to https://github.com/nextcloud/server/issues/37800

Summary

The system address book (SAB) only contains the user's primary email address. With this change additional email addresses get saved to the card as well.

Right now only additional email addresses set to federated or published are saved. With https://github.com/nextcloud/server/pull/38048 local ones will be saved too.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• [ ] Tests (unit, integration, api and/or acceptance) are included
• [x] Screenshots before/after for front-end changes
• [x] Documentation (manuals or wiki) has been updated or is not required
• [x] Backports requested where applicable (ex: critical bugfixes)