Find datasets based upon a code

[Robsteranium]

Building on #6, when you find a code you want you should be able to click and see a list of datasets that involve this code.

Initially we could just show a list of dataset names and URIs.

This could be extended to allow you to select multiple codes (e.g. from the code-search results).

We could also then show the matching-observation counts against each dataset using a query like:

{
    "size": 0,
    "query": {
        "term": {
            "sdmxd:refPeriod.@id": "http://reference.data.gov.uk/id/year/2010"
        }
    },
    "aggregations": {
        "match_obs_count": {
            "terms": {
                "field": "qb:dataSet.@id"
            }
        }
    }
}

Finally we could extent to adding link to PMD cube viewer with code-filters applied.

[kiramclean]

Done in #14/#15