Exported services CLI and docs

[dhiaayachi]

Description

This PR adds a new cli command to list exported services

command: consul services exported-services

The PR also adds the API docs for the exported services API.

CLI output
CE

$ ./bin/consul services exported-services                          
Service   Consumer Peers
backend   east, west
db        west
frontend  east, east-eu
web       east

Enterprise

$ ./bin/consul services exported-services                          
Service   Partition  Namespace  Consumer Peers  Consumer Partitions
backend   default    default    east, west      
db        default    default    west            partition-west
frontend  default    default    east, east-eu   
frontend  default    ns         east, east-eu   
web       default    default    east 

CLI output json

$ ./bin/consul services exported-services -format=json
[
    {
        "Service": "backend",
        "Consumers": {
            "Peers": [
                "east",
                "west"
            ]
        }
    },
    {
        "Service": "db",
        "Consumers": {
            "Peers": [
                "west"
            ]
        }
    },
    {
        "Service": "frontend",
        "Consumers": {
            "Peers": [
                "east",
                "east-eu"
            ]
        }
    },
    {
        "Service": "web",
        "Consumers": {
            "Peers": [
                "east"
            ]
        }
    }
]

Testing & Reproduction steps

• Tests added
• Manual testing

Links

PR Checklist

• updated test coverage
• external facing docs updated
• appropriate backport labels added
• not a security concern