Feature: support many address books

[thecyberd3m0n]

Problem:
Google Contacts App allows to add many address books from many accounts. By using OpenSync + Nextcloud we can sync many of them from one server. I've even created "blacklist" address book, which is shared among all users of instance, and publicly using URL.
Solution:
Allow user to filter contacts by address book. And allow to block whole address book.

[thecyberd3m0n]

Please let me know how can I contribute. I've got this feature working on my local branch