Handover Request Message Processing
	- AMF selection respect to GUAMI
	- UE Context Creation in CU - NGAP
	- UE Context Setup Request with HO Preparation Information according to F1AP Spec

UE Context Setup Request Processing
	- If HO Preparation Information Exists, DU process this message in another function
	- Cell Group Configuration is created from target gNB's initial cell group. Then it is updated using UE Capability
	- Reconfiguration with sync IE is prepared similar to the used one for NSA

nr_pdcp_config_set_security function signature is changed and security_mode_completed input is added because from beginning we want to set pdcp_entity's security mode completed flag to true in case of handover.
Handover Request Acknowledge message preparation is done.
After reception of RRC Reconfiguration Complete message on target gNB; Handover Notify Message is triggered