1. Remove redundant functions in AvAdapter
2. Add CurrentDevice for video device treatment
Audio device treatment should be improved in the next
stage
3. Add QSortFilterProxyModel to all video list models and
manage them together to avoid redundant function calls
4. Video device call action should be responsive to device
change as well
Gitlab: #508
Change-Id: I3df949a08bc19042b73f033139cd6ab06925c0b6