GH-4265: Add GeoSPARQL 1.1 area functions - #4266

GitHub issue resolved #4265

Adds GeoSPARQL 1.1 geof:area and geof:metricArea functions, along with corresponding area() methods on GeometryWrapper.

• geof:metricArea(?geom): Returns the area in square metres.
• geof:area(?geom, ?unit): Returns the area in an explicit QUDT area unit, such as qudt:KiloM2, qudt:HA, or qudt:AC.

CRS handling and area implementation

Note that geometries in geographic CRSs are rejected with an evaluation error rather than computing misleading planar areas from angular coordinates.

For projected CRSs, area is calculated in the source CRS. For recognised geographic CRSs, area is approximated on the source ellipsoid using a local equal-area projection. Geographic Polygons extending beyond the supported local projection may produce an evaluation error.

GeoSPARQL 1.1 requires a result of zero for geometry types other than Polygon.

Support for geographic CRS area calculations was added in cc67a9a.

Area units

Area units are handled separately from the existing public UnitsOfMeasure abstraction. That abstraction currently supports CRS length and angular units and does not provide quantity-typed lookup, so this change uses a small package-private AreaUnitsOfMeasure registry rather than broadening the existing public unit API. We could streamline this, but a design discussion in an issue should probably take place first.

• Tests are included.
• Documentation change and updates are provided for the Apache Jena website
• Commits have been squashed to remove intermediate development commit messages.
• Key commit messages start with the issue number (GH-xxxx)

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