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FLASHING.md says how to take a newer version of the colleague's tree (copy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

@@ -0,0 +1,53 @@
+#include <vanetza/common/position_provider.hpp>
+#include <vanetza/common/runtime.hpp>
+#include <vanetza/geonet/position_updater.hpp>
+#include <vanetza/geonet/router.hpp>
+#include <vanetza/units/time.hpp>
+#include <chrono>
+
+namespace vanetza
+{
+namespace geonet
+{
+
+PositionUpdater::PositionUpdater(Runtime& rt, PositionProvider& position, Router& router) :
+    m_runtime(rt), m_positioning(position), m_router(router)
+{
+    update_rate(m_router.get_mib().itsGnMinimumUpdateFrequencyEPV);
+}
+
+PositionUpdater::~PositionUpdater()
+{
+    m_runtime.cancel(this);
+}
+
+void PositionUpdater::schedule()
+{
+    if (m_interval > Clock::duration::zero()) {
+        m_runtime.schedule(m_interval, [this](Clock::time_point) {
+                m_router.update_position(m_positioning.position_fix());
+                schedule();
+        }, this);
+    }
+}
+
+void PositionUpdater::update_rate(Clock::duration interval)
+{
+    m_interval = interval;
+    m_runtime.cancel(this); /*< cancel previously scheduled callback */
+    schedule();
+}
+
+void PositionUpdater::update_rate(units::Frequency rate)
+{
+    if (rate > units::Frequency::from_value(0.0)) {
+        using namespace std::chrono;
+        const duration<double> interval { 1.0 / rate / units::si::second };
+        update_rate(duration_cast<Clock::duration>(interval));
+    } else {
+        update_rate(Clock::duration::zero());
+    }
+}
+
+} // namespace geonet
+} // namespace vanetza