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FLASHING.md says how to take a newer version of the colleague's tree (copy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/common/position_fix.hpp

@@ -0,0 +1,37 @@
+#ifndef POSITION_FIX_HPP_BGU14Q9D
+#define POSITION_FIX_HPP_BGU14Q9D
+
+#include <vanetza/common/clock.hpp>
+#include <vanetza/common/confident_quantity.hpp>
+#include <vanetza/common/position_confidence.hpp>
+#include <vanetza/units/angle.hpp>
+#include <vanetza/units/velocity.hpp>
+#include <vanetza/units/length.hpp>
+#include <boost/optional/optional.hpp>
+
+namespace vanetza
+{
+
+struct PositionFix
+{
+    Clock::time_point timestamp;
+    units::GeoAngle latitude;
+    units::GeoAngle longitude;
+    PositionConfidence confidence;
+    ConfidentQuantity<units::TrueNorth> course;
+    ConfidentQuantity<units::Velocity> speed;
+    boost::optional<ConfidentQuantity<units::Length>> altitude;
+};
+
+/**
+ * Check if PositionFix contains a horizontal (2D) position.
+ * At least latitude and longitude must be valid.
+ * \param posfix position fix to be checked
+ * \return true if horizontal position is valid
+ */
+bool has_horizontal_position(const PositionFix& posfix);
+
+} // namespace vanetza
+
+#endif /* POSITION_FIX_HPP_BGU14Q9D */
+