[AMF] SBI: MBS Broadcast ContextCreate Service operation

[Borjis131]

Following 3GPP TS 29.518 - Release 17.11.0

Ch. 5.6.2.2 - MBS Broadcast ContextCreate Service operation

[Borjis131]

To test the MBS Broadcast ContextCreate Service operation from the AF (this is sent by the MB-SMF to the AMF in the specs):

# MBS Broadcast Context Create request: /namf-mbs-bc/v1/mbs-contexts
curl --http2-prior-knowledge \
  --request POST \
  --header "Content-Type: multipart/related" \
  --form 'jsonData=<data.json;type=application/json' \
  --form 'binaryDataN2Information=<ngap.bin;type=application/vnd.3gpp.ngap;headers="Content-Id: ngap-sm"' \
amf.open5gs.org:80/namf-mbs-bc/v1/mbs-contexts

data.json text file and ngap.bin binary file are needed.