Page view and package download stats

[akariv]

From the server side, update our elasticsearch with package view and download stats:

For each view:

POST /datahub/dataset/{ownerid}/{dataset_name}/_update
{
    "script" : {
        "inline": "if (ctx._source.stat_views != null) {ctx._source.stat_views++; } else {ctx._source.stat_views = 1; }",
        "lang": "painless"
    }
}

For each download:

POST /datahub/dataset/{ownerid}/{dataset_name}/_update
{
    "script" : {
        "inline": "if (ctx._source.stat_downloads != null) {ctx._source.stat_downloads++; } else {ctx._source.stat_downloads = 1; }",
        "lang": "painless"
    }
}