gatt: Add descriptor to the database
gatt: Add descriptor to the database

Initial support for GATT characteristic descriptors. This patch adds the
characteristic descriptor attribute to the GATT local database based
on the fetched GDBusProxy objects.

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