obexd: Add SetPhoneBook function for dummy back-end
obexd: Add SetPhoneBook function for dummy back-end

Current PBAP dummy implementation has a fixed root folder:
$HOME/phonebook. It doesn't follow the fixed PBAP virtual folder
architecture, it only checks if the folder exists in the file system.

pstglia/external-bluetooth-bluez,mapfau/bluez,pkarasev3/bluez,ComputeCycles/bluez,ComputeCycles/bluez,pkarasev3/bluez,silent-snowman/bluez,pstglia/external-bluetooth-bluez,mapfau/bluez,pkarasev3/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,pstglia/external-bluetooth-bluez,ComputeCycles/bluez,silent-snowman/bluez,silent-snowman/bluez,mapfau/bluez,pkarasev3/bluez,silent-snowman/bluez,mapfau/bluez