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FLASHING.md says how to take a newer version of the colleague's tree (copy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/facilities/detail/reference_position.ipp

@@ -0,0 +1,96 @@
+#include <vanetza/asn1/its/ReferencePosition.h>
+#include <vanetza/asn1/its/r2/ReferencePosition.h>
+#include <vanetza/facilities/detail/macros.ipp>
+#include <vanetza/geodesy/geodesy.hpp>
+#include <vanetza/units/length.hpp>
+#include <limits>
+
+namespace vanetza
+{
+namespace facilities
+{
+
+static_assert(Longitude_oneMicrodegreeEast == 10, "Longitude is an integer number of tenth microdegrees");
+static_assert(Latitude_oneMicrodegreeNorth == 10, "Latitude is an integer number of tenth microdegrees");
+
+units::Length distance(const ASN1_PREFIXED(ReferencePosition_t)& a, const ASN1_PREFIXED(ReferencePosition_t)& b)
+{
+    using geodesy::GeodeticPosition;
+    using units::GeoAngle;
+
+    auto length = units::Length::from_value(std::numeric_limits<double>::quiet_NaN());
+    if (is_available(a) && is_available(b)) {
+        GeodeticPosition geo_a {
+            GeoAngle { a.latitude * tenth_microdegree },
+            GeoAngle { a.longitude * tenth_microdegree }
+        };
+        GeodeticPosition geo_b {
+            GeoAngle { b.latitude * tenth_microdegree },
+            GeoAngle { b.longitude * tenth_microdegree }
+        };
+        length = geodesy::distance(geo_a, geo_b);
+    }
+    return length;
+}
+
+units::Length distance(const ASN1_PREFIXED(ReferencePosition_t)& a, units::GeoAngle lat, units::GeoAngle lon)
+{
+    using geodesy::GeodeticPosition;
+    using units::GeoAngle;
+
+    auto length = units::Length::from_value(std::numeric_limits<double>::quiet_NaN());
+    if (is_available(a)) {
+        GeodeticPosition geo_a {
+            GeoAngle { a.latitude * tenth_microdegree },
+            GeoAngle { a.longitude * tenth_microdegree }
+        };
+        GeodeticPosition geo_b { lat, lon };
+        length = geodesy::distance(geo_a, geo_b);
+    }
+    return length;
+}
+
+bool is_available(const ASN1_PREFIXED(ReferencePosition)& pos)
+{
+    return pos.latitude != ASN1_PREFIXED(Latitude_unavailable) && pos.longitude != ASN1_PREFIXED(Longitude_unavailable);
+}
+
+void copy(const PositionFix& position, ASN1_PREFIXED(ReferencePosition)& reference_position)
+{
+    reference_position.longitude = round(position.longitude, tenth_microdegree);
+    reference_position.latitude = round(position.latitude, tenth_microdegree);
+    if (std::isfinite(position.confidence.semi_major.value())
+        && std::isfinite(position.confidence.semi_minor.value()))
+    {
+        if ((position.confidence.semi_major.value() * 100 < static_cast<long>(ASN1_PREFIXED(SemiAxisLength_outOfRange)))
+            && (position.confidence.semi_minor.value() * 100 < static_cast<long>(ASN1_PREFIXED(SemiAxisLength_outOfRange)))
+            && (position.confidence.orientation.value() * 10 < static_cast<long>(ASN1_PREFIXED(HeadingValue_unavailable))))
+        {
+            reference_position.positionConfidenceEllipse.semiMajorConfidence = position.confidence.semi_major.value() * 100;    // Value in centimeters
+            reference_position.positionConfidenceEllipse.semiMinorConfidence = position.confidence.semi_minor.value() * 100;
+            reference_position.positionConfidenceEllipse.semiMajorOrientation = (position.confidence.orientation.value()) * 10; // Value from 0 to 3600
+        }
+        else
+        {
+            reference_position.positionConfidenceEllipse.semiMajorConfidence = ASN1_PREFIXED(SemiAxisLength_outOfRange);
+            reference_position.positionConfidenceEllipse.semiMinorConfidence = ASN1_PREFIXED(SemiAxisLength_outOfRange);
+            reference_position.positionConfidenceEllipse.semiMajorOrientation = ASN1_PREFIXED(HeadingValue_unavailable);
+        }
+    }
+    else
+    {
+        reference_position.positionConfidenceEllipse.semiMajorConfidence = ASN1_PREFIXED(SemiAxisLength_unavailable);
+        reference_position.positionConfidenceEllipse.semiMinorConfidence = ASN1_PREFIXED(SemiAxisLength_unavailable);
+        reference_position.positionConfidenceEllipse.semiMajorOrientation = ASN1_PREFIXED(HeadingValue_unavailable);
+    }
+    if (position.altitude) {
+        reference_position.altitude.altitudeValue = to_altitude_value(position.altitude->value());
+        reference_position.altitude.altitudeConfidence = to_altitude_confidence(position.altitude->confidence());
+    } else {
+        reference_position.altitude.altitudeValue = ASN1_PREFIXED(AltitudeValue_unavailable);
+        reference_position.altitude.altitudeConfidence = ASN1_PREFIXED(AltitudeConfidence_unavailable);
+    }
+}
+
+} // namespace facilities
+} // namespace vanetza