Add CLI commands to get configuration from FortiGate

[patrikspiess]

We'd like to get some configuration from a FortiGate. More specific we want to export address objects and groups and also service objects and groups.

Therefore we assume the following endpoints are needed on FortiGate:

• cmdb/firewall/address
• cmdb/firewall/address
• cmdb/firewall.service/custom
• cmdb/firewall.service/group

Your mission, should you choose to accept it, is to write the corresponding CLI commands and tools to get this information from FortiGate and output it in a JSON file.