core: gatt: Send not/ind to devices
core: gatt: Send not/ind to devices

This patch adds code that sends out characteristic value
notification/indication PDUs by obtaining the bt_gatt_server
from each device that has the associated CCC configured.

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