feat(contrib): add snmp2cpe

[MaineK00n]

What did you implement:

Use snmp to estimate the CPEs of typical network equipment hardware and OS.

Type of change

• New feature (non-breaking change which adds functionality)

How Has This Been Tested?

$ make build-snmp2cpe
$ snmp2cpe v2c --debug 192.168.1.99 public
2023/03/28 14:16:54 DEBUG: .1.3.6.1.2.1.1.1.0 -> 
2023/03/28 14:16:54 DEBUG: .1.3.6.1.2.1.47.1.1.1.1.12.1 -> Fortinet
2023/03/28 14:16:54 DEBUG: .1.3.6.1.2.1.47.1.1.1.1.7.1 -> FGT_50E
2023/03/28 14:16:54 DEBUG: .1.3.6.1.2.1.47.1.1.1.1.10.1 -> FortiGate-50E v5.4.6,build1165b1165,171018 (GA)
{"192.168.1.99":{"entPhysicalTables":{"1":{"entPhysicalMfgName":"Fortinet","entPhysicalName":"FGT_50E","entPhysicalSoftwareRev":"FortiGate-50E v5.4.6,build1165b1165,171018 (GA)"}}}}

$ snmp2cpe v2c 192.168.1.99 public | snmp2cpe convert
{"192.168.1.99":["cpe:2.3:h:fortinet:fortigate-50e:-:*:*:*:*:*:*:*","cpe:2.3:o:fortinet:fortios:5.4.6:*:*:*:*:*:*:*"]}

Checklist:

You don't have to satisfy all of the following.

• Write tests
• Write documentation
• Check that there aren't other open pull requests for the same issue/feature
• Format your source code by make fmt
• Pass the test by make test
• Provide verification config / commands
• Enable "Allow edits from maintainers" for this PR
• Update the messages below

Is this ready for review?: YES

Reference

[kotakanbe]

LGTM