Allow “Self” as option in “Relationship to you” field.

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

I'd like to be able to mark a contact as representing myself.

Describe the solution you'd like

Allow “Self” as option in “Relationship to you” field.

Describe alternatives you've considered

A default contact could be created that inherits the properties configured by https://wim.nl.tab.digital/settings/user, but this is a more complex version of achieving basically what this does.

Additional context

If anything, I'd like https://wim.nl.tab.digital/settings/user to be able to inherit the properties of the contact that this would allow designating as self. However, that'd be a separate issue, albeit dependent upon this.

I believe that this property should be limited to one contact, not least so that the aforestated can be eventually implemented, but until then, I see no serious reason to limit it. I still suggest it.

The issue names the “Relationship to you” field and the user settings page, but no files or tests. Start by locating that field in the Contacts app and tracing how its value is saved and reloaded. Done means a contact can be designated as “Self”; clarify whether the proposed one-contact limit is required.