Merge remote-tracking branch 'origin/e1-setup-encdec-tests' into integration_2025_w04 (!3152)

E1 Setup enc/dec library and unit test

This MR is adding a library for E1 Setup enc/dec functions:

- E1 CU-UP Setup Request
- E1 CU-UP Setup Response
- E1 Setup Failure

and relevant unit tests

openair2/E1AP/e1ap_setup.c

@@ -101,6 +101,9 @@ MessageDef *RCconfig_NR_CU_E1(const E1_t *entity)
     if (*gnbParms[GNB_GNB_NAME_IDX].strptr)
       e1Setup->gNB_cu_up_name = *(gnbParms[GNB_GNB_NAME_IDX].strptr);
 
+    // Only 5GC supported
+    e1Setup->cn_support = cn_support_5GC;
+
     paramdef_t PLMNParams[] = GNBPLMNPARAMS_DESC;
     paramlist_def_t PLMNParamList = {GNB_CONFIG_STRING_PLMN_LIST, NULL, 0};
     /* map parameter checking array instances to parameter definition array instances */