feat(api): add SNMP configuration

[cpaillet]

As OpenConfig doesn't have SNMP configuration, we use the IETF YANG model defined in RFC 7407: https://datatracker.ietf.org/doc/rfc7407/

This review includes:

• An ingestor from the NetBox-Network-CMDB SNMP API endpoint.
  netbox endpoint:

{
            "device": {
                "id": 60335,
                "name": "ra19.05.jp2.pnet.crto.io"
            },
            "community_list": [
                {
                    "name": "global_ro",
                    "community": "mufdqsdfqsdf",
                    "type": "readonly"
                },
                {
                    "name": "globalrw",
                    "community": "qsdfqsfqsfqsdfdqsdf",
                    "type": "readwrite"
                }
            ],
            "location": "loc1",
            "contact": "cc2"
}

• Generate IETF Go code from the YANG model.
• A converter to map NetBox-Network-CMDB to the YANG model.
• Create new endpoints:
  • /v1/devices/:hostname/ietfconfig

{
   "snmp":{
      "community":[
         {
            "index":"global_ro",
            "security-name":"readonly",
            "text-name":"mufdqsdfqsdf"
         },
         {
            "index":"globalrw",
            "security-name":"readwrite",
            "text-name":"qsdfqsfqsfqsdfdqsdf"
         }
      ]
   },
   "system":{
      "contact":"cc2",
      "location":"loc1"
   }
}

• /v1/devices/:hostname/config

  {
   "ietf":{
      "snmp":{
         "community":[
            {
               "index":"global_ro",
               "security-name":"readonly",
               "text-name":"mufdqsdfqsdf"
            },
            {
               "index":"globalrw",
               "security-name":"readwrite",
               "text-name":"qsdfqsfqsfqsdfdqsdf"
            }
         ]
      },
      "system":{
         "contact":"cc2",
         "location":"loc1"
      }
   },
   "openconfig":{ <..curent openconfig..>