Cellular common supported URC handlers.

Cellular common supported URC handler
FreeRTOS Cellular Library APIs callback function is called in URC handler.
3GPP URC handlers are also provided by cellular common library.
They can be used to reduce porting effort.

FreeRTOS Cellular Library callback functions	Event	Cellular common supported
Cellular_RegisterUrcNetworkRegistrationEventCallback	CELLULAR_URC_EVENT_NETWORK_CS_REGISTRATION	O
Cellular_RegisterUrcNetworkRegistrationEventCallback	CELLULAR_URC_EVENT_NETWORK_PS_REGISTRATION	O
Cellular_RegisterUrcPdnEventCallback	CELLULAR_URC_EVENT_PDN_ACTIVATED
Cellular_RegisterUrcPdnEventCallback	CELLULAR_URC_EVENT_PDN_DEACTIVATED
Cellular_RegisterUrcSignalStrengthChangedCallback	CELLULAR_URC_EVENT_SIGNAL_CHANGED
Cellular_RegisterModemEventCallback	CELLULAR_MODEM_EVENT_BOOTUP_OR_REBOOT
Cellular_RegisterModemEventCallback	CELLULAR_MODEM_EVENT_POWERED_DOWN
Cellular_RegisterModemEventCallback	CELLULAR_MODEM_EVENT_PSM_ENTER
Cellular_SocketRegisterSocketOpenCallback	CELLULAR_URC_SOCKET_OPENED
Cellular_SocketRegisterSocketOpenCallback	CELLULAR_URC_SOCKET_OPEN_FAILED
Cellular_SocketRegisterDataReadyCallback	None
Cellular_SocketRegisterClosedCallback	None