F1AP: Add gNB-DU Configuration Query IE support

This field will be adopted to trigger cgc encoding at DU,
according to the specs (see subsequent commit for details).

Changes:
- Add gNB_DU_Configuration_Query field to f1ap_ue_context_mod_req_t
- Implement encoding/decoding
- Add to cp, eq, and free functions for the new field
- Update tests to include the new field

openair2/F1AP/tests/f1ap_lib_test.c

@@ -1039,6 +1039,7 @@ static void test_f1ap_ue_context_modification_request()
   orig.drbs_rel[2].id = 19;
 
   _F1_MALLOC(orig.status, LOWER_LAYERS_RESUME);
+  _F1_MALLOC(orig.gNB_DU_Configuration_Query, true);
 
   F1AP_F1AP_PDU_t *f1enc = encode_ue_context_mod_req(&orig);
   F1AP_F1AP_PDU_t *f1dec = f1ap_encode_decode(f1enc);