Preparation Work for N2 Handover

This MR introduces preliminary improvements to support !3334 (merged).

Refactored utility NGAP functions

• Moved allocAddrCopy to NGAP utilities

Decoding Functions for NGAP IEs:

• Added common decoding functions (decode_ngap_guami, decode_ngap_UEAggregateMaximumBitRate, decode_ngap_nssai, etc.)
• Adopted these functions across the NGAP stack

Improvements to RRC and Handover Handling:

• Enhanced get_neighbour_cell_information and get_neighbour_config to differentiate input parameters (cell by NR Cell ID vs. gNB by PCI)
• Used byte_array_t in nr_initiate_handover
• Introduced RRCReconfigurationParams_t to structure RRCReconfiguration IEs
• Added a function to build NR_RRCReconfiguration_IEs_t
• Adopted this approach in do_RRCReconfiguration and refactored the function
• Refactored the handling of Dedicated NAS message list
• add masterKeyUpdate handling in RRCReconfiguration generation

PDCP Re-Establishment Improvements:

• Enabled PDCP re-establishment for SRB1/SRB2 based on a bitmap in createSRBlist (3GPP TS 38.331 RadioBearerConfig)

NH & KgNB Key Management:

• Added NH derivation function as per 3GPP TS 33.501 A.10
• Moved KgNB derivation function to key_nas_deriver utilities