Family tree

Is your feature request related to a problem? Please describe.

The contacts App has a field "Related contacts" which allows specifying relationships like Mother, Child, Brother etc.
Currently, this information is not used.

Describe the solution you'd like

I propose a family tree feature which uses the "Related contacts" field to display a graphical Family Tree.
It can be very similar to the organization charts feature recently introduced.

This idea was originally mentioned in https://github.com/nextcloud/contacts/issues/2730#issuecomment-1285181382

Describe alternatives you've considered

No response

Additional context

To simplify specifying the "Related contacts", having https://github.com/nextcloud/contacts/issues/1046 would be very helpful.
However, plaintext entries should still be possible for relatives not in the contact list.
Also, having an option to select "Me" or "[username]" as related contact would be helpful, since people typically don't have themselves stored as contact, but most contacts will have some relation to the user itself.

Start by reviewing the organization charts feature in PR #2726 and the related-contact discussion in issue #2730. The requested result is a graphical family tree based on Related contacts, while retaining plaintext relatives and considering self or username relationships; issue #1046 provides additional context for entering relationships.