Configuring Biocache UI

We'll expose the sampled field as a facet in the Biocache UI. This way, we alter the UI to change map and charts.

1. Add facet in biocache-hubs to expose the added layers and [[sampled and indexed data|Sample-And-Index.md]. See /data/ala-hub/config/grouped_facets_default.json and add an entry to one of the sections.
2. Add a chart for your facet. See /data/ala-hub/config/charts.json.
3. Add a WMS overlay to the map. See /data/ala-hub/config/overlays.json. You can use this file as a template.
4. Restart tomcat and test with some search