Cache contacts of remote address book
I'm using a Librem 5 Linux phone with a Nextcloud remote address book for my contacts. However, sometimes the remote address book might not be available. This results in an empty address book in the GNOME Contacts and the GNOME Calls applications. It would be really helpful if the remote contacts are somehow cached or stored locally, so that they can be used when the remote Nextcloud address book cannot be reached.