PBAP: Add support for handling connection state

This patch adds support for updating connection state for pbap server
on settings UI. A new flag is added to allow settings sub menu to
show pbap preference only when remote device has intiaited pbap
request and not for all devices for which user has started/accepted
pairing request from remote device.

Change-Id: I3ba777a6be4a6321a260739b9a87a8c6054a74d3
CRs-Fixed: 758697