feat(v1.1): Implement new /health endpoint for v1.1

The new /health endpoint of v1.1 is different from the /health
of v1.0. In v1.1 /health endpoint we will return a set of KPI
(Key Performance Indicator) of the target Marconi server. The
API response will be like below:

{
    "mongo_pool_1": {
        "message_volume": {
            "claimed": 0,
            "total": 0,
            "free": 0
        },
        "storage_reachable": true,
        "operation_status": {
            "create_queue": {
                "seconds": 0.0021300315856933594,
                "ref": null,
                "succeeded": true
            },
            "post_messages": {
                "seconds": 0.033502817153930664,
                "ref": null,
                "succeeded": true
            },
            "list_messages": {
                "seconds": 0.000013113021850585938,
                "ref": null,
                "succeeded": true
            },
            "claim_messages": {
                "seconds": 0.0013759136199951172,
                "ref": "3f515f37-58a0-4c81-8214-3e92979b82e7",
                "succeeded": false
            },
            "delete_queue": {
                "seconds": 0.0030739307403564453,
                "ref": null,
                "succeeded": true
            }
        }
    },
    "mongo_pool_2": {
        "message_volume": {
            "claimed": 0,
            "total": 0,
            "free": 0
        },
        "storage_reachable": true,
        "operation_status": {
            "create_queue": {
                "seconds": 0.0011799335479736328,
                "ref": null,
                "succeeded": true
            },
            "post_messages": {
                "seconds": 0.024316072463989258,
                "ref": null,
                "succeeded": true
            },
            "list_messages": {
                "seconds": 0.000008106231689453125,
                "ref": null,
                "succeeded": true
            },
            "claim_messages": {
                "seconds": 0.000576019287109375,
                "ref": "68629fda-b4ce-4cf9-978a-df0df8df36a7",
                "succeeded": false
            },
            "delete_queue": {
                "seconds": 0.003300905227661133,
                "ref": null,
                "succeeded": true
            }
        }
    },
    "catalog_reachable": true
}

docImpact
Implements: blueprint detailed-health

Change-Id: I6b281132e2fef8ce65ce54b9d6be297571f8b170
Merge "feat(v1.1): Implement new /health endpoint for v1.1"