library: NGAP encoding/decoding using libfftranscode

This allows us to encode/decode 3GPP NGAP messages, as used on the
N2/NG-C interface control plane between gNB and AMF.

asn files fetched from https://forge.etsi.org/rep/int/5g-core/ngap.git
directory ttcn/LibNGAP/lib/asn1, commit
fa43d01e202379a969e991a9454d9c6c6930b5b5.

Change-Id: Ia8e29c77e09a4388c774e3d7286f96052d67fe3f
---
A library/ngap/NGAP_CommonDataTypes.asn
A library/ngap/NGAP_Constants.asn
A library/ngap/NGAP_Containers.asn
A library/ngap/NGAP_EncDec.cc
A library/ngap/NGAP_IEs.asn
A library/ngap/NGAP_PDU_Contents.asn
A library/ngap/NGAP_PDU_Descriptions.asn
A library/ngap/NGAP_Types.ttcn
A library/ngap/regen_makefile.sh
9 files changed, 12,171 insertions(+), 0 deletions(-)