framework/src/ble_manager: Add disconnect casue on callback

[ziyik]

-Add disconnect cause on callback
-Modify disconnect handle to pass disconnect cause to application callback
-Modify examples to support the disconnect cause on the callback

[giwon-nam]

I have confirmed that the cause is properly delivered to the callback.
It seems that the build is failing, so we may also need to make the same modifications in the rtl8720e side.

[giwon-nam]

TizenRT/os/board/rtl8720e/src/component/bluetooth/example/ble_central/central.c

Line 151 in e9c1e84

client_init_parm->trble_device_disconnected_cb(disconn_ind->conn_handle);

There is still a build error occurring. It seems that modifying just the line of code mentioned above will resolve the issue.