Add other vector format support using the OGR library

#### Issue details
Is it possible to add the option to load a polygon from vector formats other than shapefiles please? OGR drivers support many formats, e.g. GeoPackage (see: http://www.gdal.org/ogr_formats.html). It would be a nice addition to be able to use these.

#### Version
Any

Many thanks

No files, tests, or entry points are named. Start by locating Mission Planner's existing shapefile polygon-loading path and investigating how OGR support could be integrated; done should include loading polygon data from non-shapefile vector formats such as GeoPackage.

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