Filter accessions by GeoRegion

The Country is linked to its GeoRegion and regions follow hierarchical structure as shown at https://sandbox.genesys-pgr.org/geo/regions

Please allow for filtering of accession data by geographical region:

• Add Region of Origin filter above Country of Origin
• Add Region of Holding Institute filter above Country of Holding Institute

The filter should display the region hierarchy in a select box. Region "World" should not be presented.

I should be able to select more than one Region (e.g. "Northern Africa" and "Western Asia") in the filter.

The filter should also include countries of all sub-regions of selected region and apply the resulting set of countries to the database query.

ES

With conversion of selected regions to list of countries the elasticsearch query should still work.