Bluetooth had two public types with similar name _bt_gatt_ccc and
bt_gatt_ccc, but for absolutely different purposes.
That caused misunderstanding of relationship of them and cases
where to use which one.
Commit changes name of _bt_gatt_ccc to more suitable by usage and
improves documentation of it.
Additionally, it changes name of BT_GATT_CCC_INITIALIZER
to correspond the type name.
Signed-off-by: Aleksandr Khromykh <aleksandr.khromykh@nordicsemi.no>
b53b5e198a