Added separate templates for Aquabrowser and Summon

Each item in the results list (shortrecords) has it's own template, depending on which API has been specified. Currently, we are still using the predefined models to populate the templates. This will change to dynamic models where all the retrieved metadata will be stored (so we will not be making a manual selection of properties any longer). This will allow us to generate format-specific templates, populated by the given metadata.
This function is doing quite a lot of separate things. I wonder whether you could split it up into different functions all handling one specific task.
As an example you could have `_renderResultItem` and `_renderResultItems` (which would handle the recursion).
Then have something like
```
// Render the result items templates
var itemTemplate = 'partials/find-a-resource/api-results-aquabrowser';
if (results.results.api === 'summon') {
    itemTemplate = 'partials/find-a-resource/api-results-summon';
}

_renderResultItems(results.results.items, itemTemplate, function(err, renderedItems) {
    if (err) {
        ...
    }
    
    var templateParameters = _.clone(params);
    templateParameters.search.results.items = renderedItems;
    // Render the results list template
    res.render('partials/find-a-resource/api-results', templateParameters, function(err, tplResults) {
        ...
    });
});
```