Support all NextCloud-supported contact attributes.

[RokeJulianLockhart]

Checklist

• [X] I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• [X] I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• [X] I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• [X] I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• [X] This issue contains only one feature request.
• [X] I have read and understood the contribution guidelines.
• [ ] I optionally donated to support the Fossify mission.

Feature description

NextCloud exposes

to the user.

Why do you want this feature?

Because there is no mobile contact manager advanced enough to support these attributes, even though most are RFC-standard.

Additional information

https://help.nextcloud.com/t/what-attributes-does-nextcloud-contacts-support/182314/1?u=rokejulianlockhart