Keep the colleague's microbu-esp32c5 tree in this repository

obu-firmware builds against vanetza-idf from microbu-esp32c5/external, but
that tree was gitignored, so a clone of this repository could not build the
firmware it ships. It is now committed here as ordinary files in its own
folder, microbu-esp32c5/: the colleague's commit cf4b99f plus the V2X2MAP
bridge's signature verification (--trust) used on the bench. Nothing is
fetched from or pushed to the colleague's repository; this repository and
its remotes carry everything. The folder's own .gitignore keeps build output,
downloaded components and private key material out, as it did there; the
committed file set is identical to that repository's tracked files.

The ESP32-C5 is still flashed from obu-firmware/, which only takes
vanetza-idf from microbu-esp32c5/, so the two stay separate folders.
FLASHING.md says how to take a newer version of the colleague's tree (copy
it over the folder, rebuild, test, commit).

microbu-esp32c5/external/vanetza-idf/vanetza/geonet/areas.hpp

@@ -0,0 +1,101 @@
+#ifndef AREAS_HPP_CVK1NIAI
+#define AREAS_HPP_CVK1NIAI
+
+#include <vanetza/geodesy/geodesy.hpp>
+#include <vanetza/units/area.hpp>
+#include <boost/variant.hpp>
+
+namespace vanetza
+{
+namespace geonet
+{
+
+using geodesy::CartesianPosition;
+using geodesy::GeodeticPosition;
+using geodesy::distance;
+using geodesy::local_cartesian;
+
+struct Circle
+{
+    Circle() : r(1.0 * units::si::meters) {}
+    units::Length r; // radius
+};
+
+struct Rectangle
+{
+    Rectangle() : a(1.0 * units::si::meters), b(1.0 * units::si::meters) {}
+    units::Length a; // center to long side
+    units::Length b; // center to short side
+};
+
+struct Ellipse
+{
+    Ellipse() : a(1.0 * units::si::meters), b(1.0 * units::si::meters) {}
+    units::Length a; // long semi-axis
+    units::Length b; // short semi-axis
+};
+
+struct Area
+{
+    boost::variant<Rectangle, Ellipse, Circle> shape;
+    GeodeticPosition position;
+    units::Angle angle;
+};
+
+double geometric_function(const Circle&, const CartesianPosition&);
+double geometric_function(const Rectangle&, const CartesianPosition&);
+double geometric_function(const Ellipse&, const CartesianPosition&);
+double geometric_function(const decltype(Area::shape)&, const CartesianPosition&);
+
+/**
+ * Canonicalize a point in a shape's coordinate system w.r.t. its azimuth angle
+ * \param point Point to canonicalize
+ * \param azimuth Azimuth angle of shape's long side
+ * \return canonical position (suitable for geometric_function)
+ */
+CartesianPosition canonicalize(const CartesianPosition& point, units::Angle azimuth);
+
+/**
+ * Check if positon is within or at border of area
+ * \param area with shape, dimensions, azimuth and center point position
+ * \param position Geodetic position to check against area
+ * \return true if position is inside or at border
+ */
+bool inside_or_at_border(const Area&, const GeodeticPosition&);
+
+/**
+ * Calculate area size in square km.
+ * \param area Area object
+ * \return area size
+ */
+units::Area area_size(const Area&);
+
+template<class SHAPE>
+bool inside_shape(const SHAPE& shape, const CartesianPosition& p)
+{
+    return geometric_function(shape, p) > 0.0;
+}
+
+template<class SHAPE>
+bool outside_shape(const SHAPE& shape, const CartesianPosition& p)
+{
+    return geometric_function(shape, p) < 0.0;
+}
+
+template<class SHAPE>
+bool at_shape_border(const SHAPE& shape, const CartesianPosition& p)
+{
+    return geometric_function(shape, p) == 0.0;
+}
+
+template<class SHAPE>
+bool at_center_point(const SHAPE& shape, const CartesianPosition& p)
+{
+    return geometric_function(shape, p) == 1.0;
+}
+
+} // namespace geonet
+} // namespace vanetza
+
+#endif /* AREAS_HPP_CVK1NIAI */
+