Location definitions for aviation collections

[juerg1s]

Within the Aviation profile, location definitions should provide the
following metadata as a minimum:

For FIR (Flight Information Region) (SIGMET collection)

• A polygon with the borders of the FIR (represented as a list of float latitude and longitude)

For Airports (TAF and METAR collection)

• A Position with the coordinates of the airport (represented as float latitude and longitude)
• A definition of the altitude of the Airport

Required Properties (All aviation collections)

• The Name of the Entity
• The ICAO Identifier of the Entity