Refactor (F1AP/RRC): convert SIB containers to byte_array_t

Unify SIB container handling by introducing a typed SIB enum and storing
SIB payloads as byte_array_t across common NR types, F1AP helpers, MAC,
and RRC DU setup code.

Changes:
- Include byte_array support in nr_common.h, add nr_sib_type_t (NR_SIB_1–NR_SIB_21),
  and change nr_SIBs_t to hold only nr_sib_type_t SIB_type.
- Switch f1ap_sib_msg_t in f1ap_messages_types.h to use a byte_array_t SI_container
  instead of raw pointer and length fields.
- Update F1AP encode/decode, equality, copy, and free helpers in
  f1ap_interface_management.c to work on SI_container.buf / SI_container.len and
  use eq_byte_array, copy_byte_array, and free_byte_array.
- Adapt F1AP tests in f1ap_lib_test.c to build and inspect SIB containers via
  SI_container.buf and SI_container.len.
- Replace magic SIB numbers with nr_sib_type_t values in gnb_config.c
  (get_sys_info and fill_du_sibs) to validate and configure DU SIBs.
- Rework nr_mac_configure_other_sib in NR_MAC_gNB/config.c to decode SIB2
  from a byte_array_t container, fix freeing by releasing the decoded sib2 on
  failure, and use NR_SIB_2 / NR_SIB_19 for CU/DU SIB selection.
- Add an add_si_msg helper in rrc_gNB_du.c and refactor the SIB2 branch of
  rrc_gNB_process_f1_setup_req to populate cell->SI_msg from encoded local
  byte array while iterating SIBs with FOR_EACH_SEQ_ARR.

openair2/COMMON/f1ap_messages_types.h

@@ -161,8 +161,7 @@ typedef struct f1ap_du_register_req_s {
 
 typedef struct f1ap_sib_msg_s {
   /// RRC container with system information owned by gNB-CU
-  uint8_t *SI_container;
-  int SI_container_length;
+  byte_array_t SI_container;
   /// SIB block type, e.g. 2 for sibType2
   int SI_type;
 } f1ap_sib_msg_t;