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FLASHING.md says how to take a newer version of the colleague's tree (copy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

@@ -0,0 +1,103 @@
+#ifndef PATH_HISTORY_HPP_1ITSMS5I
+#define PATH_HISTORY_HPP_1ITSMS5I
+
+#include <vanetza/facilities/path_point.hpp>
+#include <boost/circular_buffer.hpp>
+#include <boost/range/iterator_range.hpp>
+#include <cstddef>
+#include <list>
+
+namespace vanetza
+{
+namespace facilities
+{
+
+// C2C-CC BSP RS_BSP_318 path history (Method One) parameters
+extern const units::Length cTraceAllowableError;
+extern const units::Length cTraceMaxDeltaDistance;
+extern const units::Angle cTraceDeltaPhi;
+
+/**
+ * Implementation of Path History Reference Design (Method One)
+ * \see NHTSA Document "VSC-A Final Report: Appendix B-2" from September 2011
+ */
+class PathHistory
+{
+public:
+    struct Parameters
+    {
+        units::Length allowable_error = cTraceAllowableError;
+        units::Length chord_length_threshold = cTraceMaxDeltaDistance;
+        units::Angle small_delta_phi = cTraceDeltaPhi;
+        units::Length retention_distance = 500.0 * units::si::meter;
+    };
+
+    PathHistory();
+    explicit PathHistory(const Parameters& params);
+
+    /**
+     * Consider one further path point for inclusion into path history
+     * \param a path point, expected to be newer than any previously given point
+     */
+    void addSample(const PathPoint&);
+
+    /**
+     * Drop all samples and concise points, e.g. on pseudonym (AT) change
+     */
+    void clear();
+
+    /**
+     * Get current reference point, i.e. last provided path point
+     * \return current reference point (fallback is a default constructed PathPoint)
+     */
+    const PathPoint& getReferencePoint() const;
+
+    /**
+     * Get concise list of path points
+     * \note previously given path points are only included if the algorithm
+     *       presented in above mentioned document as "Method One" selects them
+     * \return list of path points, some given points might be omitted
+     */
+    const std::list<PathPoint>& getConcisePoints() const { return m_concise; }
+
+    /**
+     * Newest concise points covering at least a distance (crossing point included)
+     * \param distance minimum distance to cover
+     * \return view of the newest concise points
+     */
+    boost::iterator_range<std::list<PathPoint>::const_iterator>
+    getConcisePointsMinLength(units::Length distance) const;
+
+    /// As above but capped at max_points
+    boost::iterator_range<std::list<PathPoint>::const_iterator>
+    getConcisePointsMinLength(units::Length distance, std::size_t max_points) const;
+
+    /**
+     * Newest concise points covering at most a distance (crossing point excluded)
+     * \param distance maximum distance to cover
+     * \return view of the newest concise points
+     */
+    boost::iterator_range<std::list<PathPoint>::const_iterator>
+    getConcisePointsMaxLength(units::Length distance) const;
+
+    /// As above but capped at max_points
+    boost::iterator_range<std::list<PathPoint>::const_iterator>
+    getConcisePointsMaxLength(units::Length distance, std::size_t max_points) const;
+
+private:
+    void updateConcisePoints();
+    void truncateConcisePoints();
+    const PathPoint& starting() const;
+    const PathPoint& previous() const;
+    const PathPoint& next() const;
+
+    Parameters m_params;
+    boost::circular_buffer<PathPoint> m_samples;
+    std::list<PathPoint> m_concise;
+};
+
+} // namespace facilities
+} // namespace vanetza
+
+#endif /* PATH_HISTORY_HPP_1ITSMS5I */
+