core/gatt: Expose extended properties
core/gatt: Expose extended properties

This patch reads the extended properties for characteristics that have
the necessary descriptor. Updating the "Characteristics" property is
delayed for services until the extended properties have been read for
all of their characteristics that have them.

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