card: handle sticky profile flag via messaging api

This is the same as !551 (closed) but implemented using messaging API only. Corresponding UI change is pavucontrol!60 (merged)

New card database entry version 5 for card profile is sticky flag. New messaging API handlers set-profile-sticky and get-profile-sticky.

When card profile is sticky, always restore it even if it is unavailable, and prevent switching from it when ports become unavailable.