Feedback: HTTP discovery API for metrics

```
GET /v1.0/:tenantId/experimental/views/metrics
```

Response:

```json
{
    "values": [
        {
            "name": "mzdfw.available",
            "unit": "unknown"
        },
        {
            "name": "mzdfw.average",
            "unit": "unknown"
        }
    ],
    "metadata": {
        "count": 2,
        "limit": null,
        "marker": null,
        "next_marker": null,
        "next_href": null
    }
}
```
You can optionally specify a filter query parameter if you want to supply globs like

```
GET /v1.0/:tenantId/experimental/views/metrics?filter=ord.*
```
I'll add documentation to 10 minute guide once we have a way to spin elastic search from within docker.