Add Nominatim query functionality

#### Description:
Nominatim (from the Latin, 'by name') is a tool to search OSM data by name and address (geocoding) and to generate synthetic addresses of OSM points (reverse geocoding). It can be found at [nominatim.openstreetmap.org.](https://nominatim.openstreetmap.org/ui/search.html)

Would be good to access queries to the nominatim api from OpenStreetMap_Toolkit
This will provide a way of working with OpenStreetMap queries without knowledge of defining search location by latitude and longitude.

API documentation is here https://nominatim.org/release-docs/develop/api/Overview/

Initial functionality should include:

- Input of the search string
- Run the query via HTTP adapter

As multiple results are likely these should include:
- a way to easily check (maybe a url to the map showing the area or object found)
- a `BH.oM.Adapters.OpenStreetMap.IOpenStreetMapRegion` to use for onward search
- a `BH.oM.Adapters.OpenStreetMap.Node` at the centroid of the region to use for onward search

@rwemay other thoughts for initial functionality?