aerial_lib: include header instead of source file

Expose needed (n)FAPI procedures to aerial_lib ( both P5 and P7 ) via a
header file.
Move (n)FAPI P7 packing/unpacking function interface into separate header file
Include needed headers in aerial_lib

nfapi/oai_integration/aerial/fapi_vnf_p5.c

@@ -32,7 +32,6 @@
 #ifdef ENABLE_AERIAL
 #include "fapi_vnf_p5.h"
 #include "fapi_vnf_p7.h"
-#include "nfapi/open-nFAPI/nfapi/src/nfapi_p5.c"
 #include "nfapi/open-nFAPI/vnf/inc/vnf_p7.h"
 
 extern RAN_CONTEXT_t RC;

nfapi/oai_integration/aerial/fapi_vnf_p7.c

@@ -31,7 +31,7 @@
  */
 #ifdef ENABLE_AERIAL
 #include "fapi_vnf_p7.h"
-#include "nfapi/open-nFAPI/nfapi/src/nfapi_p7.c"
+#include "nr_nfapi_p7.h"
 
 extern RAN_CONTEXT_t RC;
 extern UL_RCC_IND_t UL_RCC_INFO;

nfapi/oai_integration/aerial/fapi_vnf_p7.h

@@ -45,6 +45,7 @@
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
+#include "nfapi_interface.h"
 #include "nfapi_nr_interface_scf.h"
 #include "nfapi_vnf_interface.h"
 #include "nfapi_vnf.h"