Finish view model for contact list

Part of #90 (closed). The view model should also handle filtering of the contact list while searching.

added Sponsor 7 label

added S: in progress label

assigned to @ialokim

mentioned in merge request !33 (merged)

added S: in code review label and removed S: in progress label

closed with merge request !33 (merged)

changed milestone to %Desktop 0.1.0